Sentence rating has been discussed before. It's not a bad idea, but I think there are too many sentences (at least for the top few languages) for it to work well. Take English. If, say, 500 English sentences are rated every day it would take around one whole year before every English sentence was rated.

If there was a rating system I think it would be better if a select subset of the popular languages were singled out for rating. 5,000 is probably a handy number. After a while, low rated sentences could be dropped out of the 'select few' and others selected to replace them.

I'm going to use this space to again push forward the idea of an optimized algorithm that invites users to review sentences/translations that they are most fit to review via a popup sidebar ;-)

my bad, I've forgotten to restart the autocompletion server. It should be back now

for historical / architecture reason

Some languages, mostly non latin alphabet one, sometimes require a "latin alphabet" version or something to help the occidental learner to read it. So the second grey line is used for this purpose (you can try with chinese or shanghainese).
Before for japanese we used romaji, but it was really innacurate, the software we used was producing bad result etc. so we moved to another one, and then we decided to used katakana (sorry if I used the wrong terms :s, I mean the things in Japanese which can be assimilated to an alphabet) And then Trang decided to switch to a ruby version of this. So now for japanese it's true it's a bit "double". But for architecture reason, we cannot "merge" them for japanese, as I don't want to make a special case for japanese in the code (harder to maintain etc.)

done, search and several random should be a little faster :), and now it takes 5 minutes to reindex all the content against 2 hours before.

it is not on purpose, but consider the following,
we need a way to make people go to the page of a given sentence / translation, there's the little button on the left, but when we did it, few people clicked on them, and so a lot of people have missed this page.
So we've decided to make the text of sentences link, so yep it has the drawbacks to make difficult to select inner text. If someone know a easy and standard solution to make the "link" to become simple text when select, I will be glad to integrate it.
For the moment the workaround is to go on the page of the sentences, and on the right you have the historic of the sentences, and there you can select inner text etc.
So as you can see we had to choose between this two things which has both drawbacks.

This is a feature of your browser, not Tatoeba.

In Firefox, you can press down the Alt-key while selecting text. This will trigger the broser to "Save-As" after you've selected the text, but you can just cancel that and then copy the link.

In Opera this Just Works(tm).

Yeah, I have this problem too. I've tried Safari and Chrome on Mac OS X.