However, many new users get confused when they try to activate Akismet because it asks for an API key to get the plug-in activated so you can use it on your blog. But don’t worry, the API key for Akismet plugin comes free and it takes just a minute to generate your unique Wordpress API key. You can get your API key on your welcome email from Wordpress.

Remember, that until you get a Wordpress API key, Akismet spam feature won’t work on your blog. However you can generate one Akismet key and use it to activate Akismet on all your blogs.

How to Activate Akismet:

First, you’ll need to go to wordpress.com and sign up for a free account.
When asked, select the second option – “Just a username, please.“

After successful registration, Wordpress will send a verification mail to your email. Remember to provide a real email address. If you don’t get the email try looking at your spam folder just in case.
Open that email then scroll down there you’ll find your Wordpress.com API key. It looks like the one below on the screenshot.

Copy that API key and paste it in your Akismet API Key field. Next, click on Update.

Now, you have your Akismet plugin successfully verified and working. One last note, you can access the comments secured by Akismet when you follow a link called Akismet Spam located just below the comments tab. There, you can save any comments that aren’t really spam just in case they end up there.

Now you are finished!

Remember to save that email for future use. You might need that API key to verify Akismet on other Wordpress blogs as well.