An enterprise Twitter takes top honors at Techcrunch 50.  Go figure.  Not the first time that a new idea has been taken, improved upon, and launched.  Does this ensure wild success for Yammer?  Nope.  It is a decent bit of coverage but not the keys to the kingdom as big launch events like this generally only benefit those hosting them. 

The true test is when someone actually pays for what you are selling.

What this does mean is that micro-blogging (140 characters at at time) seems to be a for real opportunity and there could be a legitimate business reason for it at some point.