If you were supporting Microsoft stuff, you went to CodePlex and used a Microsoft-friendly open source license. Same if you were on Google Code -- chances were you had an Apache license and your code's target was fixed on a larger Google project.
This has been changing over the last year. We have covered the move by Microsoft to make CodePlex independent, targeting corporate code repositories rather than just .Net-friendly projects. Now Google is doing the same, announcing it will accept open source projects under any license, even the AGPL.
This is considered a concession, although some are calling it a birthday present, given that Google Code has now been online five years. (Time flies.)
I think it's just another example of evolution in action. Legal papers were never really needed to show that a project on Google Code was Google-centric, nor that one on CodePlex was Microsoft-centric. This was implied in the hosting.
Now open source projects have five serious choices for handling their central code repositories:
Only the last costs any serious money, but for many it will also remain the option with the greatest benefits.