Some months ago I wondered whether captchas -- those annoying word-image verification systems that so many blogs use -- are really necessary. Well, now I know.
One of my recent, and rather widely linked, posts has attracted a huge amount of automated spam, linking to what seems to be a nasty spyware-purveying site. I have deleted perhaps 10 copies so far, but more keep coming in.
So, hello captchas, sorry commenters.