http://bentasker.i2p/posts/blog/security/346-don-t-use-web2tor.html
Blocking Access Ever since the inception of a Hidden Service endpoint for this site, I've blocked known Tor2Web instances (for the reasons above, as well as to avoid incurring a duplicate content penalty in Google's indexes ). Unfortunately, not every Tor2Web operator is onboard with disclosing that it's a Tor2Web instance , and so not every instance adds the X-Tor2Web header.