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.
E's flat, ah's flat too 
Rhapsody Singer
/ November 9, 2007well I being a 0 techie, read this one avidly. Liked the conciseness and the content…keep up the good work…
sharath
/ November 20, 2007Hi RahulGot here through Nanopolitan. You should probably watch the talk of the Captcha co-inventor – Louis Von Ahn. http://video.google.com/videoplay?docid=-8246463980976635143&q=luis+von+ahn&pr=goog-slHis homepage you will find other ‘games’ he has designed to harness human computation power.http://www.cs.cmu.edu/~biglou/