mjasay writes "At the Web 2.0 Summit, Microsoft CEO Steve Ballmer admitted that Microsoft 'will do some buying of companies that are built around open-source products,' suggesting that to avoid open-source companies would 'take us out of the acquisition market quite dramatically.' Ballmer has apparently come a long way since dubbing Linux a 'cancer.' The real question, however, is which open-source companies make sense within the Microsoft product portfolio, both from a technology and philosophy perspective. Novell? 37Signals? Jive? SugarCRM? And, equally importantly, which companies could look their communities in the eye after selling to Microsoft?"