Email is a great thing. It allows you to write to people very far away, very quickly. It came into popular use in the mid to late 1990s.
The Unix ID
Every Williams student gets an email account of the form email@example.com, where 07 is the graduation year and abc are the student's initials. This moniker, 07abc, is known as the student's Unix ID, and is used for logging into many different systems. If there are two students in a class with the same initials, the student whose last name comes later alphabetically becomes 07abc_2. Sometimes there is an 07abc_3, and an 07abc_4 has been known to exist, usually when there are only two initials. In all such cases, these unfortunate individuals are known as "underscores."
Ways to check your e-mail
At Williams, there are several ways to check your e-mail.
IMP stands for Internet Mail Protocol. The software was written by a Williams student, way back in the day. Few people know this. This is probably why Williams webmail runs on IMP rather than something else. There are two equivalent ways to check your mail with a web browser: http://imp.williams.edu and http://webmail.williams.edu. Most people have a strong preference for one or the other, though they are fundamentally the same.
PINE was the way most Williams students checked their e-mail until about 2003. It is a text-only system. When you use PINE, you almost feel like a real computer geek. It's not very intuitive for people who have grown up using web-based e-mail, but it is very useful because it is often up when webmail is down, so there is a whole set of directions here on how to use it.