Here's the gist of it:
You'll receive emails with links to the surveys each month.
The first month you're required to respond, and then the month after the end of every quarter (January, April, July, October).
If you have had no repairs, the response is just an approximate odometer reading and verifying that two other pieces of info are still correct. Very quick.
In other months, you just respond if you had a repair the previous month. Then you fill out a longer survey, but it's still just one page:
http://www.truedelta.com/survey.php
The email will contain an encoded link to the survey, so you won't even have to log in. Just click the link and you're there.
That's it. The site has other surveys you can fill out right away, but those are voluntary and are not required to remain a member.
I also send out monthly updates to keep people informed of improvements to the site, but it's also not necessary to read these if you haven't got the tiime.
If you have any other questions, feel free to ask them.