If you use Firefox (who doesn't?) you can easily translate everything on the web without switching to another site. It's called "Inline Translator" and is an addon for Firefox.
I use this now since 1 day and I find it very useful.
Even people with good english don't know every word and this is much easier and faster than switching to dict.cc or leo.org.
Just mark the text with your mouse and it gets translated next to your mouse pointer.