Q:
Leveling after 80?
It is the mastery system introduced with Heart of thorns. The new max “lvl” u can get is 166 i believe. You earn mastery points thriugh achievements, adventures, and communing. Mostly in the new maps. U get experience with each mastery you unlock that progresses towards the next lvl.
Because mastery points are pretty detailed, I’ll just link this
http://wiki.guildwars2.com/wiki/Mastery#Mastery_points
It explains everything, and has links to understand what will help you earn mastery points for the 2 different areas (Core Tyria and HoT zones).
Short Version: In your Hero panel under Achievements: All of those Green symbols are HoT mastery points you can earn, Red is Core Tyria. Clicking on any drop down menu will show you what you have to do (explain: HoT Act 1 story, doing it once, gives X mastery points).
The bar at the bottom of the screen shows what the experience is at for your mastery point you are working on.
Hero panel – Masteries: Shows you the options available. (Suggestion, get into a HoT zone and earn gliding 1 ASAP)
Otherwise the wiki should be able to explain every really.
The number shows how many mastery points you have spent. I found it a bit odd that when you get your first mastery the number on your toon changes from 80 to 1. In fact, I thought it was a bug. You also no longer get to see what level you have been scaled down to when you go to lower level areas. The info is still on your ‘H’ panel but not on your XP bar.