A major challenge was getting /community to not be duplicated for each domain. So www.domain1.com/community and www.domain3.com/community were showing in the search engines. Ugh.
By May 2012, the new Panda update wiped out results and sites dove from #1 to bye bye G-love. This was actually okay because the sites were not being updated, aka: they sucked.
Anyway - I've mostly ignored G, Bing, Y, and others because the sites were dead and it was time to focus on building things. After all - there is nothing like killing something "average" by advertising ...
Today - I was feeling particularly curious and looked at G webmaster tools and laughed.
The change from www.domain.com/community to community.domain.com is clear as .... but I didn't mark the change made in Dec 2012. Drats.
My take away - keep notes.