What is the cite attribute for?

Question

The cite attribute specifies the address of the source of the quoted text, I think, but who uses this information?

For example:

Answer 1

Quoted from W3Schools:

The cite attribute is not supported by any of the major browsers. However, search engines may use it to get more information about the quotation.

http://www.w3schools.com/tags/att_q_cite.asp