Jeb Bush Wants to be President (and is doing something about it?)

Well, the 2016 election is now under way:

I am excited to announce I will actively explore the possibility of running for President of the United States: https://t.co/luY4lCF2cA.
— Jeb Bush (@JebBush) December 16, 2014

I just want to know how one "inactively" explores the possibility of running for President of the United States? What does this even mean? It's not an announcement that he's in the race, or even that he's in the exploratory phase, per se. I guess it's just one of like 15 times we'll get to see him make news? I'm not sure.