More specifically, will these be available skills that provide significant bonuses to the game experience?

Speechcraft:
Will I be able to use this to unlock unique dialogue with npc's or even use it to convince certain officials within game to unlock particular quests even?

Mercantile:
This, I doubt, will be a separate skill on its own (Being apart of speech or personality), but will I, if I master it, be able to invest or even start my own business? Selling crafted items or potions etc.

Also, will Speechcraft be able to be used with other players...? If so, how would that work?