On a point of clarification drmike our Moderator and myself and everyone else who answers questions here on the support forums, except for those who have "keymaster" beneath their names, are all unpaid volunteers.
We all have blogs too that are also under constant attack by spam bots. So if you think you are the only blogger getting incest and rape and porn spam directed at your blog then, think again. Many of us remove pages of this kind of spam every day.
Luckily you can fish your own comments out of the spam filter and mark them not spam. By doing this Akismet will learn that you are not a spammer and none of your comments will be lost.
It's always recommended that comments on older posts be closed to prevent spam masquerading as comments from slipping in. As for incoming comments all of mine are moderated and that has saved my blog from being spammed many times over each day. I check out every incoming comment link before I post it to my blog.
This is how I look at it. If I had a guard dog like Akismet on duty protecting my livestock I'd have to feed the dog and give it proper vet care. I would also have to keep my gates closed and my fences in good repair. And I'd have to keep an eye on everyone coming and going through the gates. In other words the guard dog and I would become a protection team.
Keeping spam out of my blog is analogous to this. It means that Akismet has a job to do and so do I. Having the guard dog doesn't mean I can open all the gates and not bother to mend the fences.