The final sample comprised all 278 eligible participants who returned their questionnaires through the mail.?
351835
Depends on how subjects were recruited, how many subjects were in the original sample, and why they were eliminated.
191785
Heres your answer from those who took it...
427522
According to a survey it was AIM.
973281
the user didnt verify their email...\n\n\nxoxo
1171498
You get 100 invites after sending few emails and using G-Mail for around a week.
567515
Yes, I replied through mail.
250814
63 of them!  Check the website below to see them all, with contact links...have fun...
159822
25% of yahoo mail users
6721
There was a survey done a while back here is a link to it...  http://www.sizesurvey.com/result.html
571801
People from the Royal Mail, perhaps?
931917
But they all got refunds.
701649
People who graduated from a certain school.
11839
It is rolling out gradually to a set of users.  To be considered for the beta you can sign up via the link below.  Please note that this doesn't guarantee that you will be selected but it will provide info that the mail team uses to select beta candidates.
572078
The answerers before me hit the correct answer 60% of the time.  If they answered correctly 6 times, how many total answers did you receive?
609455
Lot of people have recieived the email, some have been fooled but only you seem to have posted a question and earned 2 points as well. \n\nGood going... vote me up.
727838
Dear friend \n          The answer has been sent to your maild.
366951
You can find sample letter here.