Kilgore looks at polling on the question:

Despite conservative efforts to discourage Americans (particularly young and health Americans) from buying health insurance under Obamacare, Gallup finds that about two-thirds of the uninsured say they will comply rather than doing without insurance and also risking fines. Just under half of the uninsured say they plan to use the exchanges. But an astonishing 51% of the uninsured are “not at all familiar” with the exchanges, and another 21% are “not too familiar.” Those numbers are going to change quickly, and so, too, will the numbers of those planning to use the exchanges (and take advantage of the tax subsidies available to those with incomes under 400% of the poverty line), and those understanding their lives just got better.

Kliff bets that few will buy insurance today:

If you’re an insurance shopper, buying coverage Tuesday doesn’t make a ton of sense. Your policy won’t start until January, but you will have to pay your first month’s premium right away. There’s no advantage to being first in line to sign up for health coverage.

The Congressional Budget Office expects 7 million people to enroll in the new marketplaces this year. There’s not going to be a lot more that we know Oct. 2 about whether the White House can hit than goal, beyond what we know this very moment.