Moved from: https://www.w3.org/Bugs/Public/show_bug.cgi?id=16137

Discussions:

http://lists.w3.org/Archives/Public/public-webapps/2011JulSep/1528.html
http://lists.w3.org/Archives/Public/public-webapps/2011JulSep/1537.html

Critical bit: how do we do this such that the answer isn't obsolete as soon as it's given, since there are no transactions over the set-of-databases.