One way to make sense of this is through the Aristotelian idea that friends function as a kind of mirror of each other: insofar as friendship rests on similarity of character, and insofar as I can have only imperfect direct knowledge about my own character, I can best come to know myself both the strengths and weaknesses of my character by knowing a friend who reflects my qualities of character.
To the extent that friends function as trade partners, the volume of incoming benefits should influence closeness.
On this view, friends function as exchange partners, from whom gains in trade can be profitably extracted, provided that cheaters can be avoided.
Finally, if friends function as allies, then possible mechanisms can be drawn from existing theory in international relations, since nations have had to solve exactly the same problem assembling a network of friends who provide support in conflicts.
And according to Homestore, the company in Westlake Village, Calif., that owns Realtor.com, visitors to the site used its "e-mail a friend" function to send more than a million listings during the second quarter of this year -- though a majority of those were probably sent by the prospective buyers.
On the PlayStation 3 most games have their own separate friends list and some have no friends function at all.
Hermione, by contrast, who establishes the Society for the Protection of Elfish Welfare despite the ridicule of her friends, functions "rather consistently at the Level 5, obeying the rules consistent with her internal moral code and breaking those that are not".
Unfortunately, unlike Yo, the new Yo, Hodor doesn't have a "find friends" function, so you have to add friends by name.
Nimbuzz has made over the user interface of its Android app (which currently looks like an orange-skinned "WhatsApp"), including the promotion of its "calling" and "meet new friends" functions to the home screen.
Either way, avoid the temptation to use the "Suggest to Friends" function because it's even less effective than sending group messages.
Escort her to family and friends' functions such as picnics, weddings, holiday parties, etc.
