There was another thread about this just a couple of weeks ago:
bitcointalk IP logI'll quote what I said in that other thread below. There are other parties you have to take in to consideration (not just bitcointalk.org), and even if you fully trust all parties involved (you shouldn't), things can still go wrong. If you are concerned about your privacy, you should take steps to improve or protect it yourself.
Even if Bitcointalk plan to delete your data or limit its retention as described on the "About privacy" page (linked to by actmyname above), you have no way of confirming that is happening, and are relying solely on trust. Data can be hacked, can leak, can be copied or backed up (intentionally or accidentally), and so on. Third party services such as Cloudflare and Captcha providers will also almost certainly be recording more information and data than Bitcointalk does.
If you are concerned about your IP being tracked or linked to your real identity or your data being collected, then you should be using a brand new email address, a brand new alias, brand new bitcoin addresses, and so on, all done over Tor. Don't trust other people to look after your privacy for you.
