Step 12: Now it’s time to activate the plugin on your hosted blog! So close the WordPress page and open up the admin control panel on your hosted blog (the one you actually use) and click on Plugins to view your plugin menu.
Step 13: You should see Akismet as a listed plugin on your plugins page. Click the Activate link to enable the plugin on your blog.
Step 14: You will get a confirmation box that says the plugin has been activated, as well as a box saying your need to enter the API key for the plugin to work properly. Click on “enter your WordPress.com API key”.
Step 15: Enter your API key into the form by hitting Ctrl-V to paste it, or simply type it in from the email you received. Click the Update API Key button and the red box indicating that your key is invalid will disappear.
Step 16: Your DONE! You can see the Spam the plugin catches by clicking on “Manage” on the menu bar, then click “Akisment Spam” to view the full list of captured Spam. You can either delete the Spam manually, or let the plugin do it automatically… it will auto delete Spam older than 15 days.
Hope this tutorial helps you get Spam under control on your blog!