When someone asks this question, I'm seeing potentially two parts:
- A prospective company (actually the content management organization and individuals vetting solutions) is doing its due diligence. It's making sure it doesn't get burned and is considering the big picture.
- Those looking to disqualify you.
But since SDL Tridion is decoupled between content management, delivery, and even distribution, it's almost guaranteed server technology will be able to support more users than your organization can.
Here's the good and bad news, depending on how you look at it.
The content management industry--the CMS professionals and content management users themselves, not the vendors, are pointing out that "Big Content" has its costs. Just read a few posts by Content Strategists to see the importance of creating a content matrix or inventory, of having a strategy, and focusing on your end-users' (visitors') needs (learn about top tasks by Gerry McGovern). The paradox of content is more isn't necessarily better.
The other part is users should not be the only number you're looking for. The ability to scale is a question an organization needs to confirm with both its vendor and itself.
In terms of content authors (users), are you ready to:
- Train them now and into the future (please don't expect to successfully cram 25 users into a session and though "train the trainer" works to an extent, do you really have trainers in your organization?)
- Support them (any system or technology has support costs--I'm de facto "iOS support" for my daughter's iPad for example)
- Convince them to change from their existing systems
Technology has the ability to transform and change roles but also to disrupt existing processes and even people. If you're asking if SDL Tridion or any system can support X users, be sure to account for the change. If done right, you'll be able to do more with the same.
- Some will get to do less manual work
- Some may do more technical work
- Some may do more analysis, design, and content modeling (my favorite)
So have a plan on the benefits and trade-offs (especially in personnel) for a new system. Change leadership matters.
The real question you should consider:
- How much content do you have
- How often will you update it
- What systems does it live in today
- Where do you want that content to live tomorrow (it doesn't all have to be in the CMS)
Is having X users actually a benefit? Are you looking forward to it? Is your organization ready for X users?
SDL Tridion, as a piece of technology (it's an application backed by database(s) like many many others not quite like it) can support as many users as you need. The real question is how many do you really need? How many can your organization support?