Q: What's this?
A: It's what Slashdot looks like in Opera 11.50.
Q: Why is it broken?
A: Apparently they ran out of forward slashes during the work on the last update? Here's their HTML:
<a class="btn link slashtvico" href="http://tv.slashdot.org"><span>SlashTV<span></a>
The "SlashTV" link is supposed to be an icon and thus they use a quirky combination of styles to hide all the text inside it and display an image instead (this is a technique known as CSS image replacement).
Since they didn't close the tag properly, the pre-HTML5 parser thinks all remaining content on the page is inside the SPAN, and applies styling like text-indent: -999999px; to make all the text on the site disappear.
I wonder what their code will look like when they run out of dots too!