Occurence of "?" in the body content leads to body being combined with the subject and also content after "?" is truncated
<a href="mailto:[email protected]?Subject=Your Friend Wants to Share A Link&body= <%=str%>">Email to a friend</a>
The last questionmark in an href is used to split query from path. You should url-encode your parameters. Since you seem to be using ruby, you can just use url_encode ( http://rdoc.info/stdlib/erb/1.8.7/ERB/Util:url_encode ).