& is an & sign when encoded for correct presentation in text so in html
you would say Bill & Ben in your code and it would be presented as Bill
& Ben in the browser. You would only use it in a URL if you wanted to pass
Bill&Ben as an argument. The & sign on the URL is for gluing querystring
parameters together.
The proper character for an url is & BUT in an HTML document the & character
introduces a character entity. For this reason, when a link is written
inside an HTML document it's better to use & to avoid a possible
confusion. Note that this is an HTML issue, in particular the server will
still see just & (as this is what & means in an HTML document).