A thought just occurred to me about translation engines in general, and since I most frequently use your dictionary, I thought this would be the best place to throw it out there.
One thing I notice that your site's dictionary does very well is that it recognizes that a word can be translated one of many ways, depending on how the writer is trying to use it. the word even, for instance, has tons of possible translations depending on which meaning you're going for. Your dictionary developers get that, and so they throw out all posssible idioms, phrases, etc. so that the reader can get the exact translation for which they're looking.
What would happen if we applied that same principle to text translation? (i.e. Translation rather than Dictionary) At the moment, the translator--yours and every other one I've seen--just goes with its best guess for what the writer intends to say, instead of asking the user. What if it did ask the user, though? Something AJAX-y that pops up, highlighting the word and giving the different possible meanings they could be going for. The user clicks on the one they meant, and once the user has selected their intended meanings, it translates the text. As a student-teacher for Spanish who has seen their fair share of horribly translated text, I think that the average user wouldn't mind in the slightest doing the choosing and clicking if it meant accurate translations: that's the whole point of doing the translation, right? And this would save the programmers from having to do as many context-sensitive translation algorithms, since the users are telling them the context.
I think that might be the next big step in sentence translation, short of putting every single possible sentence ever written into the database to check against, which would be prohibitively slow. You already have the possible meanings inside of your dictionary translation tool; they'd just need to be put into the database and tied to their corresponding word in the other language (which is cheaper and easier since it doesn't require programmers in order to do that).