Replacing term "hashtag" with "hash mark" to prevent spread of misinformation

According to RFC 3986, the identifier following the number sign ("#") character is called a fragment identifier. Hashtag is a microblogging concept, and the terms should not be used interchangeably when referring to the structure of a URI.

Proper usage of hashtag, i.e. "Thanks for recently favoriting my hashtag-less tweet talking up this book."