The POP3 Email feature allows you to check your email, for example, you can check your Yahoo! Mail for new mails with that Plus! feature...
POP3 is also applied at email clients, for example, Outlook and Mozilla Thunderbird, which downloads your mail through the POP3 protocol...
(Em should I use the word protocol there? Dont really remember...)
* f1d0d1d08989 slaps myself for not remembering it...
EDIT: Haiz. Posted it too slow. Results in another post...Arrg.