In our case, the two reasons they cited were "market too small," and "lack of expertise in this domain (by TSF)". Unfortunately, there isn't anything we can do about them feeling they don't have sufficient expertise in enterprise knowledge management and collaboration software, but the market size thing was obviously just a communication breakdown on our part, since the market for this stuff is farking huge. This time, our application will focus a lot more on the current market opportunity, and hopefully we'll be accepted.
And ultimately we're not even limiting ourselves to just "knowledge management and collaboration." That's just where we're starting. The goal is to provide quality Open Source solutions up and down the stack, that A. don't suck (like most enterprise software), B. have excellent UX, C. are well integrated (with each other and with external systems), and D. use cutting edge technology to address the highest-value customer problems.
Once we ship our first couple of products, and get that initial toe-hold / purchase point and are able to start accelerating, we are going to shake things up in the enterprise.
[1]: Fogbeam Labs, the up-and-coming Open Source collaboration / knowledge-management company. http://www.fogbeam.com Go there now and sign up for our newsletter. It's not necessary for you to spend the rest of your day thinking about how cool Fogbeam Labs are, and how much you want to email all your friends and tell them about us too. But if you can remember a time when you were really excited about a company like Fogbeam Labs, then think back to those feelings and how that made you feel, and do the right thing.