Why did Typepad make a Wordpress Anti-Spam Plugin?

I ran the new Typepad Anti-spam plugin for over a week and both Typepad and Akismet identified exactly the same comments as spam. I deleted Typepad – no need to have both.
This makes me curious. Why did Typepad write their own plugin? If part of the plugin’s accuracy is due to how many people have installed it, was it so that Typepad could provide their users better protection by expanding their coverage?
Akismet charges for commercial use of their plugin. Did Typepad offer this to undercut Akismet’s income?
Curious minds want to know!

