Here's a contribution from the folks at VPRO which enables spam filtering on the commenting module, via the Akismet service.

If I get the chance, I'll make a patch file out of this for readability, but it should be noted that:

• Forum 2.0 also provides a similar feature - but the current commenting module still depends on 1.x of course.
• Magnolia 4.4 will introduce the possibility to pre-execute models, which is where this functionality should be plugged in.