There's a lot of research dating back to the early days of hypertext on automatic link insertion, but afaict it hasn't really caught on in any system, whether hypertext or wiki-based, with the exception of those somewhat spammy content farms that auto-cross-link their articles. Wikipedia has indeed spawned a new wave of such research, e.g. (random example pulled out of Google Scholar): http://www.cs.waikato.ac.nz/~ihw/papers/08-DNM-IHW-LearningT...

I'd be curious how good the results are. I've found a bunch of articles, but no live demo. If someone set up a small-scale version where you compare the auto-linked version of a few hundred Wikipedia articles with the existing manually-linked version, I think that could convince people it was worth adopting (if the results looked good).