I want to know about a critical issue and which is very hot these days in our university. There is a site www.tendollarsmail.com and it gives dollars criteria as given below:
1) Each e-mail when checked is worth at least 2 US$ and it goes to 5 and 10$.
2) The e-mails are basically advertisement.
3) If someone invites his friends to open tendollarsmail account, he is granted with down line payment as follows (it is percentage of each mail which will be given to you if your friend checks the e-mail and levels are about reference levels means if someone gives refers his friend to open account then it is level 1 and if that friend refer his own friend to open the account then it is level 2 and so on till level 4).
Level 1 - 7% payment for each mail checked
Level 2 - 1% payment for each mail checked
Level 3 - 1% payment for each mail checked
Level 4 - 1% payment for each mail checked
Please shed some light on it.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

Your question included several matters.

The first matter:

It is permissible in principle to take a prize for opening an e-mail account in the site by the company owning the site because they benefit from the one who opens an e-mail account in its site, in return for a fixed prize that is agreed upon between the two parties.

However, if the company cheats and deceives the companies that want to advertise through it, like conditioning on the visitors to read the ads of that advertising company, while this is not achieved,  then there is cheating and deception, and the Prophet said: "Whoever cheats is not one of us." [Muslim]

The second matter:

The ruling on the e-mail containing commercial ads depends on the nature of the ads. If the ads are about something forbidden, like intoxicants, or includes something forbidden, like pictures of women scantily dressed, then this is not permissible, but if the ads are not about something forbidden and do not include something forbidden then this is permissible.

The third matter: The ruling of taking a fee for referring people to this site is in principle permissible, but if this includes advertising for forbidden matters, or the ads include forbidden matters, then this is helping in sin and Allaah Says (what means): {Help you one another in virtue, righteousness and piety but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment.}[Quran 5:2] In addition to this, the fee for this advertising should be definite and known, as it is not permissible for the fee to be unknown. It is prohibited for the fee to be unknown, and the fee being dependent on the number of visitors who would visit the site through you is not known, and then the others who would enter again by these visitors and so forth.

Allaah Knows best.