Secretary of Health and Human Services Kathleen Sebelius says in a new op-ed that the Web site has undergone a "dramatic improvement" since its launch two months ago, but she's still urging people not to overload the site.

In the USA Today op-ed, Sebelius urges Americans to visit the site during "off-peak" hours -- generally in the morning or at night.

"For those who prefer to shop online, you may want to visit in off-peak hours when there is less traffic — mornings, evenings, or on weekends," she writes. "Have your information ready when you log on, and comparison shop to get the best deal."

Sebelius says the site will also urge people visiting during busy times to come back later, allowing them to sign up for an alert.

"For times when there is high demand, there is a new online queuing system that allows users to opt to receive an e-mail when it's a better time to come back," she writes.

Here's more of the op-ed:

As a result, today's user experience on is a dramatic improvement over where it was on Oct. 1. The site is running faster, it's responding quicker and it can handle larger amounts of traffic.

Now, there will be exceptions, and (as with any website) we will continue to make improvements. But the system is now working smoothly for the vast majority of users.

There are many ways to sign up for coverage: online, by phone, in person and by mail. In many cases, you can also directly enroll through an insurance company.

To those Americans who have experienced difficulties online: Please do not give up. There is help available. You can call our 24/7 call center at 1-800-318-2596 for assistance in 150 languages. You can also find in-person support in your area(