Of course it is, but its also a clever strategy to capitalize on engineers who might be feeling poorly about their own company at the moment. As recruiters know, there are a lot of great candidates just under the surface (or 'loose in the socket' as a manager of mine once said). This kind of thing might make them more likely to see employment elsewhere, and like car dealers that offer a free 'umbrella hat' if you will let them get 'first crack at a deal' you can capture some good talent if you are the first company they talk to.

The story helps Yammer reach out to those people and offer them a conversation.

If anyone does go interview there, ask what they they are doing about software patents. One interesting trick would be to let the employee/inventor retain ownership and sign over only a license to the company.