What are skill points, rank and fame for?

After numerous searches I still can't figure this out.

- What are skill points for or what do they mean?

- What is rank for or what does it mean?

- What is fame for or what does it mean?

Saw a posting equating rank and fame but still don't know what they do for you.

Thanks.

skill points u get by levelling (?) and u can use em to buy skills off trainers

a skill point and some gold is needed to purchase a skill from a skill vendor if you were not able to get that skill from a quest

rank and fame are from PvP. I don't know if you can get fame from the random team arenas, but I know you get fame points from wins in tombs. Enough skill points gets you more rank, and when you type /rank you do an emote with an animal based on what your rank is.