Below is from the FAQ page.

Am I allowed to create more than one account?

Each user is allowed only one paid-for account created via Steemit.com, however users are allowed to create multiple accounts on the blockchain. Creating additional accounts on the blockchain requires users to pay their own account creation fee for any additional accounts.

What are other ways to create an account on the blockchain besides using Steemit.com?

If you are willing to pay your own signup fee, then there are other ways to create a new account on the blockchain.

There is a third-party tool called AnonSteem that accepts bitcoin, Litecoin, STEEM, or SBD to anonymously create a Steem account. You do not need to have an existing Steem blockchain account to use the service, but there is a charge on top of the blockchain account creation fee for using the service.

There is also a third-party tool called SteemConnect that allows you to create accounts by paying or delegating the account creation fee. There is no additional fee to use the service, but does require an existing Steem blockchain account to pay the account creation fee to create the account.

Why do I need to provide my email and phone number?

To create an account on the blockchain, it costs STEEM tokens. When you create an account through Steemit.com, Steemit Inc. is supplying the tokens to pay the account creation fee. In order to prevent users from abusing the paid-for signup and creating multiple accounts, we need to be able to verify that each user is only signing up for one account.

Who are they paying the account creation fee and there are other ways to verify accounts. selling our details is not the only problem, they can also give fed our details if the are pressurized.