Keywords provide you another method for further segmenting your database into useful groups of contacts. You can learn more about Keywords here.
To add a new Keyword to your database, under your Manage Your Account menu, select Manage Database Lists:
The body of the Manage Database Lists page contains all of the lists that you can edit in expanded form. You can work with individual database lists by clicking their name in the Lists box to the right:
After you've clicked Keyword List, your page will refresh displaying only this list:
You can add new Keywords by clicking the Add button in the top right corner. You'll then see the below dialog:
Just type in your new Keyword and click Save Keyword. If you had added a new Keyword for "Golf", you would then see it in your list of Keywords, as below:
Keywords have both Edit and Delete options beneath them, meaning you can edit their name or delete them entirely.