POP.

[answerbok]

what's the difference between a Point of Presence and a Post Office Protocol? and which one is the POP3?

[shybearuk]

POP3 is a Post Office Protocol. Point of Presence? Have no clue...

[lisaj]

In the olden days, an ISP didn't have a single 0845-style number because the telco didn't provide that kind of service. Instead they have local numbers around the country (or world), and had banks of modems in exchanges there. For instance, Compuserve would have a few access numbers in Sheffield, and quite a lot of access numbers in London. You used to have to tell it where you where and it would recommend a number to you that was local, and therefore cheaper. These were calles "Points of Presence". Thesedays, they're defunct because an ISP can have one number point to a centralised location.