This is a question that I recently asked on LinkedIn. I received many good responses which will be considered in the design of Tachyon CMS. Below are responses to the question.
Mike Carson
Community size and support, ease of use, expandability of the CMS, the amount of available “add ons”, licensing types, and most of all -SECURITY and how issues are handled when they arise.
Dave Bergschneider
Content and how it is managed (ie publishing workflow). Too often do consumers make the mistake of judging a CMS for what features it has. However without a solid core of Content Management everything else is useless. Second feature after content is the syndication of content and how well can I disburse the content around the web.
Sean Cook, MBA/TM – Salyris Studios
Well, it depends on your needs. Each client has different needs and budgets, but the Joomla! CMS framework has usually met the criteria for most our projects. Since Jooma! is free Open Source product with a large support community with lots of extensions and modules to use, it is hard to beat.
But again, it depends on your or the clients needs that really need to addressed up-front before deciding on a particular CMS framework. Sometimes one coded from scratch is needed, but that will cost you.
To answer your question directly, I would say flexibility with lots of extensions and modules to easily install.
Joanne Terrans
easy to use, flexible reporting functions.
Johnny Rivera
1. Simplicity and Ease of Integration into a design. While also giving me the freedom to use it in any design, not just grid based designs.
2. Content Management, not only manage articles but files, links, and media.
3. Security, and Community. I am a firm believer of not reinventing the wheel. A great community brings about new and exciting features.
4. Lightweight Period… Joomla and similar CMS, although great. It’s just too much and time consuming to develop for either one without getting deeply involved with the system.
Sita Bhatt
The ease with which one can edit content (e.g. WYSIWYG), control over custom styles and export to different publish formats like html, pdf, etc.
Anton van der Voorn
We at Lectric, a leading Dutch full service internet agency, tend to avoid answering cms feature questions directly. Not because it is not important, but first one need to identify relevant selection criteria. Then you will know which features you need to look at and which are not important to your and your case. To mention some preconditions up front:
- industry standards techniques
- a well experienced network of implemention specialists
- well documented software application (up to date)
- active end user community
- well documented development road map
- relevant and comparable reference projects
Rob Aaldijk
Fit for purpose 
Jeff Rogers
Simplicity. You WILL need to extend it for your specific needs, and a simpler system is easier to extend than a complicated one.
Henning Sund
I’ve been selecting CMS for several projects and employers. The shortest answer here: “Fit for purpose” is probably the most correct and precise. If I was about to set up a CMS for a web-only service, I’d probably look for a cheap, reliable, flexible solution.
But for a complex multi-site operation, publishing in several channels, with lot of editors and probably a few hundred journalists producing thousands of articles every day, I would focus on different aspects:
* integration towards other systems (ad handling, classified, print production systems, CRM-systems, statistical systems etc.)
* security
* stability
* scalability
* ease of use for journalists
* advanced front page management
etc.
Raju Thammala
Hi Johan,
According to me one needs to think on the usability and scalability when you think of any application or solution. In today’s date i rate SharePoint as the best CMS solution available. For any one planning to buy or develop a CMS system i think we need to keep these features in mind. Versioning, WorkFlow, Security, Reporting, Storage and Backup. I might have missed something out but this is what i have on the top of my mind. Let me know if that helps 
sathish sampath
The best thing that i would look for a CMS is combination of performance and ability to fit in design and concept.Robustness and ability to accept and handle complex pagination updates and customization is what i would be looking for when i would be looking for a CMS
Marco Sajeva
The most of the CMS are specialized: it means that they are built for a specific task and then the project get generalized.
In an open source CMS I look for community support, a solid framework (to develop custom modules on my own) and, most of all, security!
In my experience, it could be a winning point, if you are planning to manage several installations to find a solution can be centralized (to do update in one single point).
Luigi Morelli
As a chief of technical development of our CMS (Xmanager) I may say that the most important feature of a CMS is semantic web and ontology compliance.
When your data model is structured to follow those directives, flexibility, usability, integration, efficiency can easily be achieved in less time.
Feel free to contact me if you need more infos about it.
L.Morelli@mclink.it
Mitch Pirtle
Someone give Rob Aaldijk a gold star, as he hit the target dead center. There are so many platforms available that you need to marry the purpose of the site with the profile of the site administrators.
Some CMS, like Joomla, are dedicated to simplicity and ease of use. The side benefit is a massive community (over 200,000 forum users!) and tons of available extensions.
Others, like Drupal, come from developer roots that are more centered around tools and extensibility. If ease of use isn’t such a factor for you, or customization is, then you should look here.
Then there are others that break the mold – Plone, RadiantCMS, and Mephisto. They all have advantages and disadvantages.
Finally we have the commercial platforms, which honestly aren’t all that different from their FOSS counterparts.
As a founder I’m biased to Joomla, but I can also tell when another platform provides a benefit in a given situation.
Ultimately you need to determine the needs of the site, and the profile of the people using it. Once you have those requirements it is much easier to decide on a CMS platform.
Martin Wessel
Lots of good answers here, and very unbiased. But I have one criteria above all else: Documentation. It doesn’t matter how flexible the CMS is if I can’t understand it. The workflow doesn’t matter if I can’t figure out how it works. I don’t care about the size of the community if I feel like the only one who doesn’t get it.
Now, documentation comes in many forms, including third party books, tutorials, and posts for newbies in the forums. But my favorite comes from the developers, or a dedicated team working with the developers. Why? Because it shows me that the developers are interested in more than just cramming in new features. They’re proud of their system and they want you to understand it.
For example, I work with Joomla on a regular basis. Now, the developers documentation isn’t the greatest, but they do have a getting started manual that will help a new user get up to speed, and there are tons of tutorials written by third party developers and a slew of books available. That makes me like Joomla. I’ve looked at Drupal a number of times, and they have a pretty solid documentation as well.
After documentation? Ability to customize (which requires more good documentation), active user community, active development, available third party add-ons including templates, a good developer – user interaction, and an attention to details such as proper HTML generation and security.
Herman Hiemstra
Ease of use and security.
Cheers!
John Haydon
Johan,
Ease of use. Check out DIYThemes.com. They have a CMS for WordPress that is simply the best out there. I use it for CorporateDollar.Org.
John
www.CorporateDollar.Org
Massimiliano Miecchi
In this moment, I would say Access Lists.
David DeVillers
I think ADAPTABILITY would need to be the most important feature – the ability for the user to have the system adapted to his/her requirements quickly and easily by the developer. This includes integration with outside data types and interfaces. ReproMAC DFS and ReproMAX/MHC PDM fit many of these requirements.
Dan Ball
Depends on your role in the decision. First and foremost it has to support the architecture you have available, work on the OS, available script support or framework support and the like.
Beyond that it’s all about suitablity for the task and usability for the content managers.
Jonathan Tobin
Flexibility and and an active developer community. It is important to me that the presentation end be easily customizable and not tied to deeply into what is going on behind the scenes. Many CMS make this mistake, and this makes it expensive to get a front end that one is completely satisfied.
Active developer community means that you will have an easy time getting support, and a greater chance that something that you wish to do has already been done by someone else, precluding the need to redevelop the wheel, as it were.
Hope that is helpful!
Ann Donnelly
Easy update of templates, ease of use (including installation), reliability, clear instructions, support, search engine friendliness, flexible add-ons. We usually develop our own rather than use something off the shelf.
Bas Cost Budde
Ability to bend only when asked and at the requested location.
That aside:
If the CMS is used for a ‘pure website’ (information broadcast): security and robustness.
If there will be some level of interaction like on an Intranet: administrative coherence, aka consistent design, and the right level of separation between content and presentation
If it will likely be extended (I shouldn’t say modified): a very high level of internal abstraction and a correct application of OO principles.
Joe Eastham
The single most important, and often overlooked, feature of any CMS is ease-of-use for content editors and other end users.
Shambi Broome
Content Management. Not only from the developers side but also the clients side. Can I explain to a client how to use the CMS without rewriting the operation manual? Add-ons are also very important since this can affect how scalable the CMS can be.
Duane Storey
It depends on the client and the project requirements. From a developer’s perspective, a CMS that is easy to extend and also to theme is extremely important. While Drupal is very powerful, I’ve previously found it rather cumbersome in both of those areas. WordPress, on the other end, is less powerful, but is easy to theme and has a very mature plugin system with a great deal of support from the community.
From the user’s perspective, the ability to create and maintain content is obviously a top concern. A system administrator probably would be comfortable creating content in Drupal, but mom and dad would probably find it tedious and challenging. So you really need to understand the end user and goals to properly decide which CMS system and features are the most important.
Oleg Rogynskyy
REVENUE!.
Ability to monetize content is key (not only by plainly putting ads there).
Thus if a CMS can’t make money for the publisher, why the heck would he use it?
Muriel Vandermeulen
Open source
Usability
Expandability
Language management
Adds ons (news, calendar, e-commerce, newsletter management, tag clouds, …)
Hector Hurtado
- open source (so I can read and modify the code if need be)
- knowledge base (to help me customize)
- extensions (to prevent me from reinventing the wheel)
- user-friendly (so I can transfer knowledge rapidly)
Rastin Mehr
An MVC framework, a well organized and simple to use template engine, a solid menu manager which provides flexible entry points to different extensions, node based architecture, folksonomy, tag based ACL, Modular Architecture.
Miles Price
- simplicity
- APIs
- A large marketplace of add-ons/correlational software
- security
- content management
- Scalability
- Integration with other platforms is essential as well
