http://bkg5ofjslnbyqvu55sjonpdyp3wmfsgq23u7vpk3wxn7ewgdeocpgwid.onion?page=article&article=Why+You+Should+Use+a+Tor-Based+PGP+Key+Server.html
If your key is uploaded or retrieved over a clearnet server, this information may also be linked to other activities tied to the same IP address, further compromising your anonymity. Using a Tor-based key server ensures that your key fingerprint is not tied to your real-world identity.