AnkitMaheshwari - 7:27 am on Sep 18, 2012 (gmt 0)
I will go with adding solved in the Title tag itself as it might increase the CTR and hence the rankings in the long run. Though some initial short-term drop can occur on account of Google figuring out the change and user behavior.
However, there is no guarantee that Google will pick your title AS IS even if you update Solved/Answered.
PS: How good it would have been if there was a schema format to mark forum thread as answered, closed/solved,...