To enable Blogger "word verification for comments"

 
*bump*
*bump* (reposted 16 June, 16 Mar, 16 Sept 2009, 16 Nov 2009; 2 Aug, 16 Nov, 2 Jul, 2 Feb 2007; 2 November, 2 Aug, 1 Feb 2006)
*bump* (originally posted 13 September 2005)
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Blogger has added a new, sadly much needed feature to help prevent comment spam. To enable this feature on your Blogger blog, go to

Dashboard --> Change Settings --> Settings --> Comments

and check "yes" for Show word verification for comments. And that's all there is to it.

You can also choose whether or not to allow anonymous posting from a dropdown list beside Who Can Comment? on the Settings --> Comments page. The choices are "only members" (this means one must have a Blogger account to post a comment), "anyone" and "only members of this blog" (this means one must have a Blogger acount AND be a member of the blog). Unfortunately, there does not seem to be an option for disallowing anonymous posts but allowing non blogger accounts to post.