[slinkyavenger]

Using collusion without knowing what it means... Businesses make business deals all the time. If I had a company that made an inferior product and wasn't able or willing to invest time and resources to improve it, you know sure as hell I'd look to sell that product IP off before my competitors take all of my marketshare anyway and my company gets nothing for years of pre-existing work.

That's a sensible business move that lets them allocate resources to their strengths. To believe it's some kind of secret or illegal deal is pretty naïve. It's obviously not a mistake either - Hipchat is technologically behind other products on the market, and Atlassian has other core products that are doing really well (JIRA, for example).