I'm undertaking to have all article and talk page semiprotections on Wikipedia reviewed. The process I'm using is to enter a brief proposal on the article talk page and contact the protecting sysop. The idea is that we discuss whether to unprotect the article or talk page and watch it vigilantly.
This has already met considerable success, with more 30% of the proposals I've made this evening being enacted upon. There appear to be a lot of semiprotections that have simply been forgotten by the original sysop.
I'll keep this up until I either run out of articles to review or get bored. Since there are several thousand semiprotected article the latter is more likely to happen first.
Gwern Branwen wonders whether semiprotections have taken over from protections. Well one cannot really compare the current Wikipedia with the Wikipedia of 2005. Then we had no real way of dealing with biographies of living persons, and little awareness of the problem, and as for the protected articles, they numbered dozens at the most, and certainly not thousands. It's important to strike a balance. While many of the semiprotected pages may actually be redirects that we wouldn't normally want to see edited by unregistered users, I suspect many are not. It's always a good idea to review the situation regularly.