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Lots of people share Amazon Prime accounts, whether through a roommate or parent (sometimes one and the same), or friend or significant other or neighbor's orthodontist's husband.

Now the company is tightening its rules about just how many people can officially enjoy the benefits of one $99 Amazon account, which previously allowed Prime members to share the online retailer's two-day free shipping feature with four other adults.

Amazon is now saying that only two adults in one "household" can share an account. Profiles for up to four children can also be added, but those won't come with distinct login credentials. Parents can create a "family library" that lets each child set up a personalized collection of books and movies, a spokeswoman said.

Still, the change isn't actually as restrictive as it sounds. People currently registered to use friends' accounts for two-day shipping are grandfathered in—at least until the accounts come up for renewal.

And people who already share with just one person will actually see new benefits beyond free deliveries. Unlike before, joint-account holders will now also be able to share access to Amazon Prime streaming video and Kindle books. (The catch, however, is that you'll have to be comfortable authorizing the other person to use your saved credit and debit card information.)

Setting up a shared account is a simple process, as Business Insider explains: The biggest hurdle might be deciding whose credit card will get automatically charged for movie rentals. Instructions for how to "remove an adult from a household" are similarly easy (unlike in real life).

As for those folks who share one Prime account the unsanctioned way, by passing around a single username and password?

Nothing will change, and it will still be possible to share streaming video and two-day shipping, and add multiple shipping addresses and credit cards. Of course, you will technically be violating company policy—and it will be very hard to buy gifts for your spouse discreetly. But for now at least, Amazon is not going to hunt you down.