Note: If you use a browser such as Mozilla that has support for CSS3, you will see the word "off-site" display when you hover over an external link.
Here is an example link to Google.
for a long time, i couldn't decide how to link offsite pages. the way i browse -- and the most efficient way to browse, in my opinion -- is to open new windows for links that take you off a site. so this preference was reflected in the way i linked offsite pages from underscorebleach.net. i'd link everything offsite with a "target=_blank" attribute.
problem is, a lot of people don't like that, and they have a legitimate point. even though i like to browse offsite pages with new windows, lots of people like to stay in the same window, and target=_blank doesn't allow you to do that. besides, target=_blank is deprecated in the new HTML 4.01 DTD. so the smart guy at my former workplace, Adam, had a good suggestion for me: give people a choice.
so here's the deal. if you want offsite windows to open in a new window, check the box at the top of the window. offsite links will be opened in a new window, and that window will then be pushed to the background (similar to Opera's "Open in background" right-click function, which i use constantly). if you prefer not to have offsite links launch in a new window, leave the box unchecked. whatever your choice, it will be saved in a cookie for your browseriffic convenience.
curious as to how this works? probably not. but for the dorks out there, here goes...
offsite links are linked in the following way:
<A HREF="http://www.foo.com" ONCLICK="v('http://www.foo.com'); return false">link<A>
the "onclick" event handler passes the URL to a javascript function called "v". this function takes a look at whether you've decided to use offsite new windows or not, and depending on your choice, loads the URL in the base window or in a new window. if it loads the URL in a new window, it then pushes the new window to the background.
if you are in a browser without javascript, or if you've got javascript turned off, this functions as a normal link. this is a very good thing, because otherwise, people without javascript would be S.O.L.
and that's it! i wrote the code myself. yay. go me. i've never seen anyone else implement something exactly like this, but i can't take credit for the idea; Adam came up with it. you may have seen something similar on other sites that have a checkbox for opening links in new windows, but this applies to all windows, and my suspicion is that they're using a simple document.write of the <BASE> tag.