I once read a very nice definition on what a true friend is: "A friend is somebody who, when told that you are moving house, asks at what time he should turn up and help carry the furniture". We tend to have only a few friends like that. But social networks are built on "friends" connecting to each other, and in the process have very much diluted the meaning of the word. On Google+ I actually use the "Following" circle instead of the "Friends" circle for my already 134 connections. The term somehow is more appropriate.
I have 319 friends on Facebook, the large majority of which I wouldn't even recognize if I saw them, as we never met in real life. I kind of inverted the Facebook logic. Instead of inviting my real friends to play Facebook games with me, I'm inviting people interested in Facebook games to become my friends. That kind of changes the definition of what a true friend is to: "A friend is somebody who on receiving a gift in a Facebook game sends the same gift back."
I was trying out Civ World (beta) on Facebook, when somebody mentioned another Facebook game: Empires & Allies. Civ World makes very little use of your social connections, as it is subdivided into hundreds of "games", and you can only interact with the people in your game. Civ World has some interesting features you don't see very often in other Facebook games, like an actual win condition, or a $1 cap on how much real money you can spend on the game per day. But actual gameplay isn't all that interesting, and Civ World still has serious technical problems.
Empires & Allies on the other hand is a typical Zynga game. It makes massive use of your Facebook friends connections. Exchanging gifts with friends is Zynga's alternative to having to buy certain resources for cash. Obviously Zynga games have no cash spending cap, so you either advance slowly, or spend cash, or spam your friends. But "ethical" considerations like that apart, Empires & Allies is actually a better game than Civ World. Surprisingly Zynga came a long way from Farmville. In Empires & Allies you now build up an island empire with lots of different resources, use those to build up an army, navy, and air force, and then go battling either in PvE or PvP battles. PvP is limited to invading your friends and neighbors, leading to the weird situation that you'll want to visit your friends' islands to help them, only to invade that same island five minutes later. But building up your empire and battling your friends or the computer is fun enough. Hearts of Iron it isn't, but E&A is way more complex than Farmville. It just uses the same social core.
In a way these Facebook games create new social rules. If you play these games, you kind of have to accept these new rules and play by them. Thus there is a lot more spamming and begging going on in these games than would be socially acceptable in other environments. People realize that these games are built around these semi-automated messages, which makes them more acceptable. It wouldn't really make much sense to try to play these games but refuse to send out messages asking for help, or asking your friends to become your neighbors, or sending them gifts. These are essential gameplay elements which would be hard to avoid if you wanted to.
So if you are on Facebook as a friend of mine, and happen to play Empires & Allies, don't be surprised by all the spam I'm sending your way. If you're actively playing you probably need those liberty bonds like I do and exchanging them as gifts is the cheapest way to get them. If you aren't actually playing any more, just ignore me, or block E&A requests. The advantage of these Facebook friendships of convenience is that "unfriending" or ignoring people is less of an issue than it would be with real friends.