I hope it's ok to ask this as a professional who works with children rather than this being a personal experience. I work with vulnerable children, including children in care, which sadly includes some children who came back into the system after adoption breakdowns. Increasingly I've come across children who have/are actively searching for biological family on social media (siblings as well as birth parents) and children who have been contacted by birth family via the same.
I trained pre-social media when rules were very simple and easy to stick to, ie letterbox contact only, and then rights to search post 18. I'm disappointed (though not surprised) that official guidance hasn't been able to keep pace with social media developments, and it's still a relatively new area to have a basis for 'best practice'. I understand of course that the best thing for any child will be individual, but I'd be really interested if anyone has had experience of this or has any thoughts about it? For example I've read accounts from some adoptees that with the increased likelihood of meeting birth family, they wish they'd had a more honest account of the reasons for their adoption (rather than a sugar coated version) so that they could make more informed decisions as teens. There's a grey area about supporting contact, given that contact would traditionally not have been lawful (post adoption confidentiality)
Just to be clear, this is just me trying to think about things from multiple perspectives to respond better to those I support, I'm not doing research or going to quote anyone who replies. Would really appreciate any thoughts!