Not sure if the forum update has modified robots.txt or how the SEs index the forum, but I've noticed forum posts have started disappearing from the Google search results.
Example search term:
[quote:13heg5k0]site:scirra.com/forum windows phone
Notice how there's a few straggling posts that look like they haven't been recently indexed, but other than that everything relevant has disappeared.
This was my method of finding solutions to problems, and was must have been source of traffic for scirra.com?