Like more than a few people (as far as I can tell by reading through my blog and other feeds) I confess that I was more than a little gobsmacked to find out that Yammer had won the TechCrunch50 prize. It may well have been a tough field for the judges, given the number of lame Web 2.0 offerings I read about among the contestants, but I still find it hard to believe that a service that is ultimately a carbon copy of Twitter won the big prize. Before anyone signs in to the comment section to berate me, I understand that Yammer is for the enterprise, and that it has a kind of “we’re holding your employees hostage” business model, where companies have to pay a fee to “claim” the users that are chatting on Yammer using their corporate email addresses.

That said, all this sounds to me (as more than one person has pointed out) like something Twitter could roll over one morning and implement without even breaking a sweat (now that its server issues seem to be a thing of the past). Is that really a great business? On the one hand, I’m inclined to give David Sacks — the co-founder of genealogy site Geni, where Yammer was apparently created as an internal communications tool — some props for getting an idea and running with it. But it still feels a lot more like a feature that makes more sense as part of Twitter than it does as any kind of standalone business.

On the other hand, that’s what a lot of Web “businesses” seem to be: features in search of a business model, or features that are hoping to be acquired by the service that they ultimately belong with. In some ways, of course, Twitter itself seems like a feature that belongs with some other communications tool, so I guess that makes Yammer a feature spinoff from another feature of an actual tool or service. That definitely deserves a prize, but not the one that TC50 gave it.