Log in to your WP blog and go to "PlugIns" activeate Akismet - it will then prompt you to enter your API key. Akismet is very handy and will reduce your comments spam load
but the problem is, if you have many wordpress blogs and want to use the akismet plugin, you need to have multiple accounts to get more API keys. i hope wordpress team will change their policy so we only need one API key for a person not per website. -cypher.
I believe You Tube asked for it also ...I have a Video Gallery on my blog and I think I remember You Tube asking for my API key also.
The API key given to you is your personal API key to use on WordPress, I have used it on various weblogs that I run, and have never run into any troubles.
maybe it only happen to me. i have 5 blogs. all of them use different api key. if i use the same key, akismet will detect that there is another user that use the same key. that is why i had to register another account for each blog. -cypher.