The SE team put a lot of effort into the Elder Scrolls V: Skyrim vs. Call of Duty: Modern Warfare 3 promotion, I think it could be effective to try and use it to retain more users that get to our site by searching for specific questions.
We get a lot of hits on many questions for new high-profile releases in the first few days. Making them aware that they have the chance to win some very nice prizes by participating in this site might get more people to try it out and contribute questions and answers.
To make those users aware of the promotion we could display an in-house advert for the promotion
- on every question tagged Skyrim or CoD:MW3
- only for new users without accounts
My idea is that this could help improve our conversion rate, to get users to stay after they got their question answered and to entice them to try out this site and give it a chance.