求翻译：首先，人人网创建之初的一个最重要特点是限制具有特定电子邮箱的用户注册，这样就保证了注册用户尽大多数都是在校大学生。是什么意思？

First, all network founded one of the most important feature is to limit the user with a specific e-mail registration, thus ensuring the vast majority of registered users are college students.

First, the everyone net establish of the most important characteristics of the beginning is the customer registration that limits to have the particular electronics mailbox, so guaranteed the registration the customer to to the utmost mostly is all university student in school.

Beginning first, everybody net founds a most important characteristic is the limit has the specific email address user registration, had like this guaranteed the registration user completely majority all is in the school university student.

First, all networks at the beginning of creating one of the most important feature is to restrict users with a specific email registration, thus ensuring the most registered users are college students.

First, all networks at the beginning of creating one of the most important feature is to restrict users with a specific email registration, thus ensuring the most registered users are college students.