I get the number sign in the address. Not sure why, it appears on many sites. Just wondering why it happens. It is not there at first and they it appears. Hope you can help.
The # symbol also is called a hash mark, and what followed it traditionally was a location in the page. However, sites also can use it to demarcate the end of the real address and the beginning of whatever information they want to keep track of as you move through the site. On Facebook in particular, a huge amount of stuff can pile up after the hash as you navigate.
If the change happened recently then it is possible that the Facebook site updated their code.