The Common Public Attribution License (CPAL) that Socialtext submitted was approved today by The Open Source Initiative (OSI). As an OSI Certified license, CPAL should provide a solution for commercial open source application projects and companies. I expect many of the 40+ companies using MPL+Attribution licenses not approved by OSI to apply the license to their products to meet both their commercial and community needs. Keep in mind there is more to it than Attribution, but it covers network use required to close the SaaS loophole in Open Source.
For Socialtext, this marks the end of a very long process where we paved the way for others. I'm happy with the final result, which should be posted at opensource.org soon, and I'll update this post accordingly. For now, an unofficial version of the final text is here.
eWeek has a good, in-depth article on this issue.