Jeb is basically in

[Mister Mets]

Kinda early.

I think people should chill out and announce during summer 2015 at the earliest.

Waste of time and resources otherwise and you are exposed to the media way too early (see Tim Pawlenty).

Again, this is neither an announcement that he's running nor an announcement of an exploratory committee.  Just an announcement that he's "actively exploring" the possibility of running.

No one else is making announcements like that, though.

In the past, there have been potential candidates who publicly weighed their options and decided not to run (Evan Bayh formed an exploratory committee) although it seems unprecedented for a top-tier candidate to make these kinds of announcements, and drop out.

[Mister Mets]

Kinda early.

I think people should chill out and announce during summer 2015 at the earliest.

Waste of time and resources otherwise and you are exposed to the media way too early (see Tim Pawlenty).

This exactly the time to be setting up finance committees and the like. The midterms are over and the donor base is looking for signals about where to make their political investments for 2016. There's a reason Obama announced his run in Feb 2007, and that wasn't even exploratory. The year before the primaries is often referred to as the invisible primary since that is when the candidates spar behind the scenes to line up organizations, endorsements, and especially donations.

I thought the invisible primary was the stuff that was going on before anyone announces.