I don't understand why it's wrong. I can see why it would be wrong if it was done on the same forum, it's annoying but to see it posted elsewhere online doesn't bother me. I just don't feel obligated to respond to it again unless I want to copy and paste my response or post my other thoughts I have on it. I have seen same topics posted on two different websites and I have done it myself for more responses. My question is how are they going to know? Unless they do a search on your username (if you have used the same usernames for each forum) or they happen to be on the same forums as you.
On Fetlife it will be real easy to see because all they have to do it click your profile to see your activity and they will see what threads and posts you have made. I don't think they have a feature that allows you to hide your activity from anyone who isn't on your friends list like other websites usually do. Only way to hide it is if you block someone, then your profile will just be blank to them and they also have no way of sending you a message or sending you a friends request.
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Son: Diagnosed w/anxiety and ADHD. Also academic delayed and ASD lv 1.
Daughter: NT, no diagnoses. Possibly OCD. Is very private about herself.