You've got to hand it to the Atlassian team – they are seriously clever. Wikipatterns.com launched recently to give people a place to go for advice on improving wiki adoption. The content is very useful to have in one place even if what's there right now won't be new to most people using wikis. It is undoubtedly useful and Lars Trieloff from the Mindquarry team has already linked to it (Mindquarry develop a soon to be opensource wiki that's integrated with a bunch of other cool looking stuff). I'm sure other wiki vendors will be linking to it over time as well.
The really clever bit is that at the bottom of each page is:
It is of course quite reasonable that since they did all the set up work and are paying the bills they should get to be sponsors. From a marketing point of view though it's brilliant – their competitors will be linking to an instance of their wiki complete with links to Atlassian on every page. What I love most about it though, is that while it might frustrate some of their competitors, it is undeniably a really, really good thing to do for their users and users of any type of wiki. Kathy Sierra would be proud.
Now I'm not sure which section it would fit into, but my best advice for driving wiki adoption is to make sure you have a really good WYSIWYG editor in there. Learning wiki markup is a major barrier to entry for people that just isn't needed anymore. I'd add it somewhere myself and let the WikiGardener find a spot for it, but given my obvious bias I'm concerned it would just look like spam. I've previously hinted at our success in adopting a wiki by integrating our editor (we started off just using wiki markup), but haven't actually told the whole story – probably should do that at some point.