the solution to this problem is to clearly mark your external links as such. there are various (accessible) ways of doing so. one that i will be implementing on a new site shortly: a graphic in front of it, with proper alt attribute of course, coupled with a relevant addition to the link's title attribute, e.g.
Originally Posted by Devilware.net
<img src="/images/external_arrow.gif" alt="external link" /><a href="http://somewhere.com" title="go to somewhere.com (external link)">go to somewhere.com</a>