When creating a new question I want to post it on the most relevant site. But what site is that? E.g. I know from experience that stackoverflow.com is programming related, but otherwise I look at the list of sites in the bottom of all the pages, and open each potential site in a new tab and look at each of them.
After looking around a bit, I've since found Stack Exchange's Site Directory. I'd like to suggest that a link to Stack Exchange's Site Directory be placed in the bottom of all the pages along with the list of sites, so it is easier to determine the correct venue for a question.