I've seen other communities of different board software successfully use Akismet for topics/posts and I think it would be great if IP.Board supported it too.

*bump*

I wouldn't recommend that, I've experienced nothing but issues wit Akismet at communities I moderate at including my own before pulling the plug. Akismet has the tendency to wrongfully ban genuine members, for absurd things such as editing a post a couple times, posting in different threads in a certain time frame and that's only a couple issues, definitely not member friendly. It's more useful for actual blogs than forums, with forums it causes nothing but problems and you will find yourself almost constantly unbanning your genuine members and apologizing.

You can use the IPS spam service though, it serves the same purpose as Akismet except that it will only prevent registrations from known confirmed spammers and it actually does a much better job than Akismet does.

Before building out our in-house spam service, we did consider a couple of third parties, including Akismet.

The problem is, we have no control over their algorithms or availability. If it goes down, there's nothing we can do. If their algorithm seems to be blocking genuine users with normal activity, there's nothing we can do. With our in house solution, we can tweak and improve it over time to make it more accurate, and that level of control allows us to better tailor it to our customers' needs.

I've used Akismet with MyBB a few months ago and I had no problems with it. You don't necessarily have to ban anyone. Simply setting that individual's post as unapproved if Akismet flags it as spam should suffice. Furthermore, if the service does go down, you could always have it so that the post proceeds approved.