I think these are new to the tSO client, but just in case, here's what I got. Mouse-over the xp bar and you get a message:
Regular XP (killing a mob) appears to still be rewarded. If this is tied to vitality, or some new XP feature (what is quest xp?) then we'll deal with it when those systems are implemented.

Quest XP is the XP you get for finishing a quest, its the same XP you get when you kill a mob, they just broke it out now because too many people bitched about out leveling stuff now. The experience requirements for levels have been significantly lowered primarily affecting the 20 thru 70 level range.
Also, new with TSO is all of your characters will now receive a 10% experience bonus for each character at the maximum level. (Up to 50% max). You’ll also receive a tradeskill experience bonus for each character at the maximum tradeskill level. Your current experience bonus will be displayed on the character selection screen. This experience bonus can be disabled on a per-character basis by right-clicking on the experience bar.

Yah, I just haven't added the support for that yet.