@RogerBlack it looks like UK enrolment is only temporarily paused
http://www.personalgenomes.org/uk/sign-up (you get your info for free but it is publicly available online for researchers to use).
I've thought about this on and off and each time I feel positive about it I find a reason to be cautious. I like the idea of sort of donating DNA info to science but I think you have to do it assuming you could be identified (you provide other information about yourself too). It's hard to know how this information could be misused in the future and potentially could cause prejudice for relatives too.
Yesterday when I was looking at this stuff I came across people angry at really basic email list errors, which doesn't inspire confidence.
My financial situation isn't as dire as it used to be, so I feel with prices coming down it is better to pay for some privacy.