Luca de Alfaro, an associate professor of computer engineering at UC Santa Cruz has developed way to track "trust" in Wikipedia entries. Text that has lasted the longest in Wikipedia entries has a white background and is thus "trusted." Newer text has an orange background and is not (or at least "less") trusted. You can check out some random entries at the UCSC WikiLab.

This is a really interesting project, and it offers us one way to measure accuracy or "trust." Of course, text that has lasted longer is not always necessarily to be trusted, but if we recognize Linus's Law ("given enough eyes all bugs are shallow") then this is could be a really effective way of at least tracing which parts of articles are more stable.