Your site's Focus Keyword is the keyword which, according to Alli's algorithm, offers the highest, quickest potential traffic increase at any one time.
You can manually change your Focus Keyword once per day. Alli will also do it for you! From your site dashboard, you can click on the highest priority tasks to see a full task description and instructions for each task.
When adding your site, once you pick your keywords, Alli will take do a full analysis of your highest priority keyword which is called, Focus Keyword. The full analysis can take up to 30 minutes to an hour, so now's a good time to grab a cup of coffee and maybe take a short walk around the block ;)
Once the first Focus Keyword analysis is done, you'll see your Focus Keyword and your most important tasks on your site's dashboard.