Following artists and tracks gives you a shortcut to their demographic and performance metrics. UML's customized reports and alerts are based on your Followed lists, so you will need to follow artists and tracks to start receiving them. You are allowed to follow up to 100 artists and 20 tracks.
To follow artists or tracks, click on the artist icon at the top right of the page:
Search for your artist or track, and click the Follow icon next to them:
To see your followed artists or tracks, click "Your Artists" and "Your Tracks". From here, you can also unfollow an artist or track by clicking the green "Following" button.