On 8/13/14 1:22 PM, Eric Hellman wrote: > It seems that Code4Lib hasn't discussed this., though the news is 2 weeks old. It seems that there are libraries using social share tools from AddThis", a company that has been using a technology called "Canvas Fingerprinting" to track users. > > In other words, it looks like libraries are giving away the user-privacy store. > > For example, AddThis is used by my public library's Polaris catalog (BCCLS). > > I'd be interested to learn how widespread this is. It's pretty widespread in general, but I don't know how many libraries are using it, or why. It's a concern regardless of absolute numbers, because it targets people who are concerned about being tracked and have taken steps to make cookies less effective. (For example, I discard cookies at the end of each browser session, making long-term tracking ineffective.) It isn't "virtually impossible to block"; mapping addthis.com on the client computer to 127.0.0.1 (using /etc/hosts on Linux and Unix machines) does a nice job of it. But anyone who uses it really is betraying the user's trust. -- Gary McGath, Professional Software Developer http://www.garymcgath.com