Although I use a few different methods of controlling these unwanted comments, I am truly getting tired of having to deal with them on a near daily basis.
I have been keeping track of the root IP addresses these comments are originating from. I am also finding a great deal of these IP addresses are from places that apparently have little regard for what they are being used for.
For those that only occasionally splog my blog I generally will manually remove the comments from the logs, but for those that are insistent and continue to be annoying, I will simply ban the IP address, or range of addresses. Some of these offenders have been banned at the server level, which is on a case-by-case decision.
So far, there have been several Panamanian IP addresses; quite a large range of addresses apparently originating in Russia; and, a couple from China. This is also quite unfortunate as there is a remote possibility that a legitimate reader would like to post a legitimate comment, but now they will have to deal with their Internet Service Provider (ISP) to start the process of clearing their name (read: IP address).
I see this as a very serious ongoing issue that world ISPs need to address. To date, I have not seen any relevant success with notifying administrative contacts (as noted in various DNS records) for these IP ranges.
I can only suggest more site administrators start banning these comment spammers at the server level; and, perhaps a critical mass of blockages will finally get through to these ISP companies. They are just as responsible for the spamming as the actual individuals who are issuing this unwanted time wasting text.
How do you handle comment spam?