Do you remember the movie “Sliding Doors,” in which a character experiences alternate life outcomes based on whether she misses a subway or not? On the Forrester Research blog, Rob Koplowitz muses on the possibility of Microsoft Corp. acquiring Yammer Inc., the internal social communications tool not unlike Salesforce's Chatter. Will Yammer remain autonomous? Will it remain pure-play SaaS? Will it be blended into Microsoft Office? The subway doors open and close, and Koplowitz suggests that the version that finally plays out will have ramifications not only for Microsoft and Yammer but also for the way companies socialize themselves.