When you're working the GPT sites you're going to need several email addresses. Advertisers aren't interested in providing the same, or basically the same, services more than once to each address. It also helps to turn down the spam filters so their, and their affiliates, ads can get through. After all, that's what they're paying you for. And it's free to you.
LINUX MAIL- http://www.linuxmail.org/scripts/common/index.main?signin=1&lang=us
ASHEVILLE- http://mail.asheville.com/horde/index.php
THE DOGHOUSE MAIL- http://mail.thedoghousemail.com/email/scripts/loginuser.pl
GAWAB- http://www.gawab.com/
WOWMAIL- http://newwow.wowmail.com/email/scripts/loginuser.pl
MAIL- http://www.mail.com/
EXCITE- http://registration.excite.com/excitereg/login.jsp?app=em&return_url=http://e23.email.excite.com/
SPL.AT- http://www.spl.at/
BOARDERMAIL- http://www.boardermail.com/
DCEMAIL- http://www.dcemail.com/
LYCOS- http://mail.lycos.com/lycos/Index.lycos
CARE2- http://passport.care2.net/login.html?promoID=1
INBOX- https://www.inbox.com/login.aspx?gdi=true
DBZMAIL- http://www.dbzmail.com/scripts/common/index.main?signin=1&lang=us
POPSTAR MAIL- http://super.popstarmail.org/
BIG STRING- http://www.bigstring.com/
IN MAIL 24- http://www.inmail24.com/Login.aspx?AspxAutoDetectCookieSupport=1
UNLIMITED MAIL- https://secure.unlimitedmail.net/CP/auth.php?l=en
ROCK- http://www.rock.com/
AMERICA HOME- http://mail.america.hm/email/scripts/loginuser.pl
MAIL 2 WEB- http://mail2web.com/
HOTPOP- http://www.hotpop.com/index.jsp
MAIL PUPPY- http://www.mailpuppy.com/scripts/common/index.main?signin=1&lang=us
UYMAIL- http://mail.uymail.com/scripts/common/index.main?signin=1&lang=us
LOOPY MAIL- http://loopymail.com/?page_id=5
ASIA MAIL- http://freemail.asiamail.com/scripts/common/index.main?signin=1&lang=us
FISHHOO- http://mail.fishhoo.com/email/scripts/loginuser.pl?EV1=12039087554129781
SURFY.net- http://www.surfy.net/
MAIL 2 WORLD- http://www.mail2world.com/
SOFT HOME- http://www.softhome.net/signup/personal/
SNOOTY- http://www.snooty.com/
DANWORLD MAIL- http://mail.danworld.com/email/scripts/loginuser.pl
JESUS ANSWERS- http://mail.jesusanswers.com/email/scripts/loginuser.pl?EV1=12076328081530534
SAFE-MAIL- https://mango.safe-mail.net/cgi-bin/Safe-mail.net/gate/N1N-48287fbf-488b58dc
SPINFINDER- http://spinfinder.mail.everyone.net/email/scripts/loginuser.pl?EV1=12076359394896733
BLUEBOTTLE- https://mail.bluebottle.com/index.php