In the run up to DnD Next the designers seem to have categorised gamers and/or classes that focus on Combat, Roleplay and Exploration. See this quote from Mike Mearls:
"Setting aside mechanics, I think you can boil D&D down to three basic activities: exploration, roleplay, and combat."
And then in reference to classes:
If the fighter is 100% damage for example, then maybe this other class is 80% damage/combat and 20% exploration, or some other mix of game elements. Each class has its time in the spotlight, and not all classes are built expressly for combat.
Emphasis mine in both quotations
I'm familiar with players who favour combat to roleplay, and classes that excel in one and not the other. I have really no idea what these designers mean when they talk about exploration.
What qualifies exploration gaming, in D&D?
Edit: From chat, I worked out what I think sets Exploration apart is the fact the the other two (Combat and Roleplay) involve some form of innate conflict resolution; there is a goal, challenge is over come, conflict is resolved. Is there a similar analogue for Exploration?
Edit the II: Furthermore, I've specifized this to D&D, as this seems to be how this question is being answered.