Maybe if we were all using twitter already and had trouble separating business and personal contacts (like when we all stopped adding coworkers to facebook and started adding them to linkedin), this would make more sense. As it is, trying to pitch a cross between project management software, email, IM, and facebook is a hard sell to get people to use, let alone buy.

All that said, I’d love for this to work- I’m going to set up an account now and hope it catches on

My best guess is that we’ll see an adoption curve for these in-house networks something like the adoption curve for IM use in enterprise settings. Some people will resist them, sure, but the utility will be obvious and instant to many.

One more thing: at a strategic level, Yammer has neatly side-stepped Twitter’s greatest advantage, which is its entrenchment in the lives of its users. In other words, no one wants to have to convince all their Twitter friends to migrate with them to some other service. But in the corporate setting, you *expect* to set up a new social graph limited to your workmates. Nifty.