Friends lists are users that you've befriended or think have god projects, or anything, really. The latest 3 projects from any of your friends shows up on the front page, so if you like their projects, you may wish to add them to your friends list. To add to it, just go to their profile and click "add to my friends."
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To add a friend, go to their profile (called _______'s stuff). You can get to it by clicking on their username next to comments, forum posts and projects, then under their name and location (eg - Wolfie1996, United Kingdom), it should say "add to friends" - click the link, and voila! It should add that person to your friends list. To delete a person from the list, click the "X" next to their name Hope this helps.
EDIT: Outposted by coolstuff, once again But he told you about the Friend's Latest projects on the homepage. It's between "Featured" and "Selected by"
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Something on a bit of a related note, you should consider on what you consider your friends. The results given in this survey are very interesting.
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