Overages are incurred additional charges for bandwidth in excess of those contracted for in excess of 1 or more Gigabytes uploaded per month. Many times overages are due to shared programs such as Napster and AudioGalaxy that allow outside users to upload or transfer music or information from your connection. By limiting the connection time to these programs you can decrease the amount of uploads and avoid overages. The number of POPs that an ISP or OSP has is sometimes used as a measure of its size or growth rate. Each of these packets contains both the sender's Internet address and the receiver's address.
Any packet is sent first to a gateway computer that understands a small part of the Internet.
The gateway computer reads the destination address and forwards the packet to an adjacent gateway that in turn reads the destination address and so forth across the Internet until one gateway recognizes the packet as belonging to a computer within its immediate neighborhood or domain. That gateway then forwards the packet directly to the computer whose address is specified. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving messages that have been received for them at their local server. Most mail programs such as Eudora let you specify both an SMTP server and a POP server. Surprisingly though, there is no official, universal name for this sign.