One more to the chorus, got the invite today.
I did e-Rewards at one point. The site, and business, are legit.
As a way to earn points/miles it's pretty close to the bottom of the well. Outside of the initial sign-up/survey bonus you earn very little in the way of pts/miles for handing over a lot of personal info. I'd much rather spend 5 minutes and $3.95 doing some MS rather than spending an hour filling out surveys and handing over reams of personal info.