this is a good site however i will tell you one thing not to do with ant networking site never ever let them use your contact list or give you email password to any site as any site will no dought send mail to everyone in the list to say you are on that site. other than that this is a good site and facebook myspace are all the same. but if you dont want a bunch of spam as with all site set block to all the security options so you will not get mailed for every notification.
There really isn't anything wrong with this site anymore. They had issues in the past, and most of them have been rectified. While people have always been able to opt out of having their contact lists raided, Tagged has made this option more visible now (it has always been there, my address book never got raided). This site is no more or less safe for children than any other site. This site is not dangerous, the internet is dangerous.