Akismet is no longer free. It's $36 a year. I don't know about you but I'm not
paying for something that was free forever.
If you're looking for an alternative, there is Growmap.
Here is the link:
WordPress › Growmap Anti Spambot Plugin « WordPress Plugins
It's free. From the reviews I've read, it's very good. It also has a level of
protection that Akismet didn't have, a check box that spam bots can't check.
Give it a shot. At the very worst, it doesn't work as well as Akismet. It is still
better than nothing.