I’ve been a bit overwhelmed dealing with comment and traceback/pingback spam on my two blogs, sometimes having to delete up to 50 a day (mostly in the moderation queue, fortunately). My first impulse was to ban comments completely, since most people who leave comments already have their own blogs, and can carry on discussions that way.
However, I do think that comments and pingbacks are valuable, so I’ve come up with a compromise: I will allow comments for all postings in the current and previous month, but close older postings to comments. I’ll still have to deal with a bit of spam, and you won’t be able to comment on very old postings, I think that this approach will work for everyone.
How do people on commercial services, like Blogger, deal with comment spam? Do you spend a measurable amount of time every day deleting it?
Land and Hold Short 
I use Roller Weblogger. It filters out most of the comment spam using the MT-Blacklist, which is automatically updated for me (a super nice feature given how busy I am). I recommend checking out the MT-Blacklist at http://www.jayallen.org/comment_spam/ and seeing if you can incorporate it into your blogger. Otherwise, check out Roller Weblogger. It’s Java Servlet based and can connect to Postgresql or MySQL.
Can’t comment about Blogger. But when I was on MovableType I was using MT-Blacklist and closing old comments after 30 days, and that worked pretty well. Since I moved to WordPress 1.5 last month, I haven’t had a single comment spam. I installed SpamKarma, and it hasn’t caught anything. I also checked the option that blocks comments from open relays, and as far as I know that doesn’t actually tell you when it blocks stuff.
SpamKarma for WordPress does everything that MT-Blacklist does (including the automatic updates), and a whole lot more. Try it, you’ll like it.
I never get any comment spam. Blogger must have some system in place to prevent it.
I posted “I never get any comment spam” and it didn’t show up. So it will probably show up later and you’ll have to delete my extra comment along with your day’s allocation of spam.
I use blogger.com for all my ylayali.com blogs including YAFB, and have it set so that you must be a blogger.com member to make comments. I.e. no comment spam — but also, very few comments (well, it’s not like there’s much to comment on in what I say…). I’ve found that people often email me instead, but that’s no subsititute for public commentary. I don’t know the best answer, but I deliberately shied away from the whole MT thing because of the comment spam…
I’ve had one or two hits over the past month. The biggest problem was finding them. Maybe blogger is helping, maybe I’m just to obscure. Who knows.