I’ve done an ancestry test. I was half expecting to find unknown half siblings but what I actually found was lots of skeletons in the cupboards of extended family members, confirmed by lots of hard work building a family tree so I understood where everyone fitted in. I’ve made contact with a couple of my mum’s cousins and exchanged lots of family photos and history previously unknown. I also discovered that my paternal grandmother was an absolute monster who abandoned children all over the place (I only met her once, so it wasn’t upsetting). It’s been very interesting but I was expecting something awful so I was prepared for it. If I’d been expecting everyone to have behaved themselves, I’d have been quite shocked.
It’s very easy to maintain your privacy on the site. No one can contact you, except through the site and there’s no obligation on you to reply if you don’t want to. Users don’t see your email address and your user name can be anything you want it to be. Lots of people only use initials. The process can’t tell you exactly what relation someone is to you, but it can tell you roughly how closely you’re related. There are thousands of people I share something like 3% dna with who are estimated to be somewhere around 8th cousin to me, so not of much interest, but the people I knew already, or people I’ve discovered through the test have been correctly identified as the right relatives (first cousin, second cousin etc). Also, it helps you work out whether matches are paternal or maternal.
My ethnicity estimates have changed since doing the test, but it does explain that the more people who take the test, the more people they have to match you with. I’m pretty much English and Irish, with a smidge of Welsh and it has identified parts of the UK and Ireland where people with my dna can be found. This tallies with the research I’ve done on my tree, so I’m happy it’s not wildly inaccurate.
I do have some privacy concerns for the future, but it sets out very clearly what they can and can’t do with your information and they ask for your consent for various things, which you don’t have to give. I just have to keep my fingers crossed that none of my relatives murder anyone.