So, I'm too low a level to post 2 posts at once ene"

1. I remember partying with a friend once, and getting random gem shards while he was off getting kills; could someone explain how partying works, the advantages, lootshare systems, etc. Or link me to somewhere with all/a lot of information?

2. I just joined the Rogue's guild, but why's it so different than the rest? It's hidden away, I get that, but it also has a symbol on the minimap, the guild is instanced, etc.
Just seems so oddball compared to the other guilds .-.