I was working on a site, and suddenly saw that the urls were a bit funky. At the end of each url I found some hash, like this:
At first I wanted to know what was causing this. I googled it, but couldn't find anything drupal related. So I started looking into the drupal modules. I searched for hook_init. But this didn't help me. Then I googled again and finally came across this post.
Apparently it is caused by addthis. On the website I encountered the problem, only a custom block with an embedded script was used. And it contained this:
If you change the "data_track_addressbar" variable to false, it stops generating hashes at the end of urls on your site. Another problem solved!