Excellent platform and service! As a fresh explorer I just have one question. Backlinks ("pages that link here") seems to be missing. Why?

We don't have that feature on our immediate roadmap though we've experimented with it.

Basically the reason we didn't push forward with support for backlinks is that for each page edit, we'd have to examine the page you just saved, look for links to other pages, and then update those pages' lists of 'links-to-this-page'. At the same time, we'd need to examine the previous revision to see if there were any pages no longer linked to by the new revision of the page, and update those pages' lists. We've found that for our larger wikis in particular (we've got some wikis with more than 20,000 pages) this ends up being a pretty serious performance issue, both for the wiki in question and others being used at the same time. It's a solvable problem but right now we're working on a bunch of other features and enhancements. We'll keep it in mind for future work though!