Everyone is interested in different levels of anonymity, especially on the internet. Most people choose forum nicknames that they could be identified with. Once you add a general location to the 'nick' it would make it much easier to pinpoint that person.
I don't feel particularly anonymous on this forum, because the nickname I use is pretty much my given name. Everyone calls me 'sloth', and some people ONLY know me as 'sloth'. Adding my location as BC and using a tat as an avatar, well......... I might as well add my phone number.
However, I read alot on this forum before I registered and started posting
and I feel 'reasonably' safe giving up a certain amount of personal information here.
I doubt I'd ever post personal pics of myself, or my family, but that's just me. My son and I were once at a car show, and a newspaper photographer snapped our pic, and asked for our names. I instinctively said, 'No, I'd prefer you didn't publish it.' My reasoning is that if my young son's picture is in the paper, along with his name, there's always that sliver of a chance that some freak will see it, and approach him, armed with his name. But again, that's just me.
I hope that helps to answer your question.