You can use lesswrong.com/r/friends/ to only see your friends' submissions.
Also, they are listed in the Friends tab of your Preferences, so you can more quickly message them or check their userpage.
If I 'friend' you, is there any way for you to tell that I've done so?
Can others see whom I have friended?
A useful feature, but a confusing use of the term 'friend.'
Indeed. You could subscribe to people as 'friends' purely because you consider them a bad influence and wish to be sure you see their comments, the better to refute and downvote them.
It adds a "friend" CSS class to your friend's username everywhere, so you can add an user style or some other hack to highlight it. There is probably a reason LessWrong doesn't do it by default, though.
If I click on a users name it brings me to a page like lukeprog's. In the upper right of that page I see lukeprog's karma score, and I also see a button "add to friends."
Early in my use of this site there were some authors I wanted to follow, I thought perhaps "add to friends" would help me do that.
But since then as near as I can tell, "add to friends" has absolutely no functionality. Does anyone out there know any differently?