1. Around 9 p.m. on Sunday evening, Health and Human Services employees flipped a switch and the new iteration of Healthcare.gov went live. While enrollment doesn't start until next Saturday (November 15), this new site now allows shoppers to start browsing plans in advance. It looks like this:

2. This is, arguably, the starting line for Obamacare's second year. This is when people are going to start poking around Healthcare.gov, getting a sense of what is available, what it costs, and whether they want to buy it. Open enrollment this year runs from November 15 through February 15. This is a much shorter time frame for people to buy health coverage than they had last year, when the first-ever sign up period started on October 1 and ended March 31.

3. Open enrollment 2015 will be easier than open enrollment 2014 in one big way: Healthcare.gov will likely be a functional website. When the website launched in 2014, it barely worked. Just six people managed to sign up the first day. Healthcare.gov didn't even have a window shopping option. Anybody who had even a slight interest in insurance coverage had to fill out a 76-screen application before ever seeing a price tag. The sign-up process became a giant bottleneck and Healthcare.gov cratered under the crush of shoppers trying to fill out applications.

there are two reasons this open enrollment will be harder than the last

4. All signs point toward the 2015 Healthcare.gov launch going smoother. The site can handle twice as much traffic as it did last year. Staff at Health and Human Services have successfully run demonstrations of the application and window shopping processes. They have shown, in real time, these parts of the website work — a huge boon to the law. Healthcare.gov is, essentially, a store to buy insurance. And this enrollment season, it seems like the store will open on time.

5. That's the upside for the Obama administration. But it's also easy to argue that this enrollment period will actually be harder for Obamacare for two main reasons.

people who really wanted a health plan already bought

6. This open enrollment season, the Obama administration is chasing customers who sat out the 2014 sign-up period — and trying to convince them, on the second go-around, that health insurance is worth the price. The Congressional Budget Office estimates that marketplace enrollment will rise to 13 million in 2015, a 5 million person leap from those who signed up in 2014. The Obama administration arguably got the low-hanging fruit in 2014; the people who really wanted coverage — maybe because they were sick, or more financially stable — bought it. This time around, the challenge is greater: getting people who decided last year that they were perfectly happy without insurance to change their minds.

7. Obamacare's second big challenge is re-enrollment: making sure the people who bought insurance last year do it again this year. One issue that consumer advocates I talk to worry about is that, last year, people shopped exclusively on price — and bought the cheapest, least-robust coverage. That could work against Obamacare: if shoppers didn't like the plan they had last year, they could decide against buying again this year. There's also a technical challenge here, too, as Healthcare.gov has never handled re-enrollments before. While HHS sources say they're confident it will work smoothly, it's still a new and untested process.

8. The prices being posted today matter a lot. Survey after survey of Obamacare shoppers have shown this information will be the most important part of decisions about whether or not to enroll.

"the test for affordability is how many people sign up next year"

While there are 8 million Americans who thought the health plans in Obamacare were a good deal, the Kaiser Family Foundation estimates there are 20 million more who decided not to sign up. For many of them, the existing prices were too high; one survey found that 39 percent of shoppers who didn't buy coverage cited "the costs aren't worth it" as the reason.

"Eight million people clearly found it affordable, but there are millions more that didn't buy," says the Kaiser Family Foundation's Larry Levitt. "The test for affordability is how many people enroll next year, and the year after."