Rui CarmoUntil Mint comes out and we can judge for ourselves what it can do (there's an amazing grassroots marketing campaign surrounding it, but as yet little actual detail), I decided to have a go at revamping the Referrers page and implement my own variation on this technique (which, incidentally, needs a few more file_exists calls - a malicious spammer could inject filenames to be unlinked...).
We'll see how it fares against the continuous onslaught of referrer spam. As usual, I opted for a KISS solution and rolled my own back-end, plus some ultra-paranoid checks and re-use of my ban list - which is still in operation, and takes precedence.
A worrying trend, however, is the recent increase in Wiki spam bots - I keep getting idiotic attempts at editing this site (often with referrers from other Wikis, which I find to be thoroughly vandalized upon visiting), and am likely to have to come up with automated banlists for that kind of activity as well (which should be easier, since any editing attempt fails instantly).