What gives with Guilds?

[QoTL]

I apologize to moderation if this is the wrong forum.

My second day playing someone asked if I wanted to join a guild. I was very new, still feeling my way around, and joined. They haven't spoken to me since, and in fact no one from my guild ever seems to be online except me.

Now I'm STILL very new to the game.. but what gives with the guilds? What is the purpose of them? I thought it was just some fun thing to have under my name but another person mentioned to me that guilds backed up their members?? Sort of like having extra people in one's corner in the game. And I've read posts on here where you guys talk about going out fighting with guild members. Could someone explain them to me please?

Thanks!