We have a custom field called "external reference" (Type text) that holds the link to the forum post where this bugreport came from, when logging from our forum. When viewing a bugreport/feature request the text looks like:

External Reference http://talk.remobjects.com/t/compiler-error-not-seeing-indexor-by-index-override/5586

but the http link isn't clickable in maniphest; It would be great if it was.