The Internet is a collection of information stored in computers physically located throughout the world. Much of the information on the Internet is organised onto electronic pages. You'll bring one page to your computer screen, discover its contents, and have the option of bringing more pages of information. Client computers use software such as Netscape Communicator to view pages.
Server computers use server software to maintain pages for clients to access.
This is because you have a large amount of e-mail, possibly an mail with graphics attached. All you do is just leave it running and it the mail will eventually download to your computer. If you cancel it part way through you could cause the mail file to double in size, which will mean it will take longer to download. Check to see that you don't have call waiting on your line. Check to make sure your don't have another handset or answering machines plugged in on the same line.