What do you think the lower age limit should be for LiveJournal and other social networks, and why?
Many years ago, there were age restrictions at our public library. I couldn't wait until I was 12 to be allowed into the adult section.
My first adult book was the The Concubine. It was about Anne Boleyn. That book led me to a life long interest in English history.
A particular age doesn't guarantee l maturity. Also, I don't know how you check ID on a web site.
If I had to pick an age, I'd go with 12.