Don't believe the media hype or even Kos. The reality is it is still February of 2007 and Iowa is 11 months away.
You see the amazing thing that is continuously being neglected in these discussions about the 2008 presidential campaign is the potential impact of the netroots. It's being ignored for good reason, there is no real netroots darling in the race right now. The ability of the netroots as displayed in the Clark and Dean '04 campaigns, coupled with the overestimation of the amount of money it will take to win this thing is why I believe Gore could probably wait until July/August and Clark could probably wait until late April/early May.
The media will dismiss anyone who fails to raise $100 million by January but the truth (as anyone who has actually run a political campaign will tell you) is that it doesn't take anywhere near that much money to win this thing. The small states can be won by a talented group of organizers, and a strong message and a few million dollars, and victories in the small states will translate into votes in the large states on Feb. 5.
The airwaves will be saturated in Iowa (with two dozen candidates running), so really the media game will have little impact. The decision will be made by 125K Iowans, which can be greatly influenced by a great ground game that can be developed in far less time than 6 months.
2008 is a whole new digital campaign and of the candidates Gore and Clark understand this better than anyone. With the internet many of the things like phone calls and fundraisers can be coordinated through the net. The money needed to run an effective campaign is not $100 million. Really after a certain point, as the Dean campaign showed, money just ends up being wasted on stuff you really don't need. Staff, polling and targeting: these are the essentials and they don't cost $100 million.
By my estimation Clark probably has until mid to late April to make a decision, and he can raise enough money in those remaining 8 months ($15-20 million-plus with at least half online) to be a viable candidate in Iowa, New Hampshire and Nevada.
Gore could probably wait until July/August - after all of the other candidates have beaten the crap out of each other to jump in and he could probably raise $40-60 million by the end of the year. He could also put together a first rate staff (both field and national) probably within 30-45 days.
The concern right now for the candidates is peaking too soon (something Barack definitely has to be worried about) and rising negatives (something Hillary has to worry about). Hillary doesn't have to worry about peaking too soon, because she is and always has been the front-runner. She has no choice but to sprint the entire marathon and must attempt to win by convincing people she can't be beat because she's so far out ahead of everyone else.
John and Richardson are comfortable sitting back, raising just enough money and piecing together their state campaigns right now, and they're relying on Barack to sort of hold Hillary at bay.
The goal right now, as the Geffen feud shows, is for the donors. And candidates with netroots appeal like Gore and Clark don't need them anywhere near as much as Clinton, Barack, Richardson and Edwards.