Here's advice for you guys using e-rewards.. just in case no one else has mentioned this.
--You will get more offers the LONGER you are a member. When I first started a year ago, I got no more than 1 or 2 surveys a week. Sometimes even none. Now, I usually get offers 1-2 a week regularly.
--The second that email hits your inbox, do it. Don't wait, don't save it for later; do it on the spot. This is because you want to be the FIRST of a certain "characteristic" they may be looking for. This doesn't guarentee you'll get picked, but it will significantly increase your chances of being accepted for the survey.
--Think about it.. if the survey is about video games; don't tell them that you purchased 0 video games in the past 12 months. Put a more reasonable answer, I'm sure you have enough knowledge on the subject to get through a video game survey.
--If you haven't already; finish your Personal Profile. This doesn't mean that you'll get surveys faster, but you get extra cash for doing it. You don't really see the results of this until a lot later in the program.
--Lastly.. Don't anticipate surveys.. Don't wake up every morning saying "I'm going to go do an e-rewards survey!" Just let them come to you and your inbox as if it's just another part of life. You could do other free things off other websites while your waiting.
Hope this helped

Good luck!
EDIT: I see people talking about how a "Membership Ends" and what it means? Let me try to clear it up..
When your "Membership Year Ends".. It is simply a way of telling you that 30 days after that date, you have to spend all the currency that is "Subject to Expiration Rules" (75% of the money left in your account). They will NOT delete your account.. it's just a marking period.
- All e-Rewards Currency earned during any Membership Year must be redeemed within thirty (30) days following the end of the Membership Year. (For example: A Member who enrolls on August 21, 2008 is assigned a Membership Year ending on September 30, 2009 and must redeem Currency earned during the Membership Year running from August 21, 2008 to September 30, 2009 by no later than October 30, 2009.)
- Following the end of the thirty (30) day period, as set forth in Section 8.b. above, seventy-five percent (75%) of any unused e-Rewards Currency remaining in a Member's account that was earned during the just-ended Membership Year will expire, and will be removed from the Member's account. The remaining twenty-five percent (25%) of the e-Rewards Currency earned by the Member during the past Membership Year shall be automatically transferred into such Member's account balance for the next Membership Year