What do you put in a wiki? Whatever you want! It's your wiki.
For me, I feel it's a lot more than just a set of 'facts' that I've discovered about my particular interests. It would then just be a really poorly maintained subset of Wikipedia. I think the point is to make sure not to lose the personal and the personality. (That which Wikipedia deliberately avoids).
Wisdom, not facts. We’re not just looking random pieces of information. What’s the point of that? Your commonplace book, over a lifetime (or even just several years), can accumulate a mass of true wisdom–that you can turn to in times of crisis, opportunity, depression or job.
I agree with that, except to de-emphasise wisdom a little. I don't want to feel a pressure that what I put in here has to be wise. It's a place for percolation. It might turn into wisdom eventually.