Certain sites block traffic from known exit nodes, and some sites simply show a CAPTCHA due to excessive abuse, etc.
Is there a list of websites known to be troublesome for visitors using Tor?
This community wiki will list commonly used websites known to be troublesome for Tor users. These will be broken down into the following categories:
The purpose of this page is not to discuss fixes/workarounds.
If you have an update, make sure to follow the format that's been established, and the following guidelines:
4chan: Since at least 11th December 2013
Wikipedia: Since at least 8th January 2008
Mt.Gox: Warns users on signup: Attention: accessing your account via the Tor network and/or public proxies may result in a temporary suspension of your account, and having to submit documents for AML verification.8
Bitcoin Forum: User unable to signup or post messages: Spam. (Auto-ban.) You may appeal here: email@example.com . If you are using Tor, see https://bitcointalk.org/index.php?topic=99601.msg1089571#msg1089571
I've decided to test how well the top 50 websites work for Tor users, and to determine the pervasiveness of any blocking. I'm using a script that runs "torsocks midori -s http://foo.bar/" to snapshot sites. Midori is configured send a Firefox user agent string.
Results from the initial test series are here, and some exemplary histograms are here. I'll add additional text, highlighting the results, as I have time. I'll also update the image link as I include new data in the analysis.
Some websites (or services such as CloudFront) may serve rapidly loading CAPTCHA-challenge pages to Tor users. As Cammy_the_block has noted, this would skew my results, in that blocking in this way would increase apparent performance. However, I have not seen any CAPTCHA challenges in the snapshots that I've taken so far. If I do find a CAPTCHA-challenge snapshot for a given website, I can probably identify others based on size.