By putting the following code (written by User:EnDumEn) in user:YOURNAME/common.jsany external link gets an extra little symbol (⎆), which leads to a link search for that link. This is very useful for finding other articles that cite the same source.
jQuery( "a.external" ).after( function() { return jQuery( "<a>⎆</a>)" ) .attr( "href", "//sv.wikipedia.org/wiki/Special:Linksearch/" + this.href ) .before( " " ); });