This begs the question: Where do you draw the line between "data logging" and submitting the URL (or domain, I'm not certain on what level WoT would normally operate) to a server in order to get its reputation? In the end, you can't be certain what the backend does with the data just by looking at the extension code. If you go too far with a rule like that, you'll likely block a lot of legitimate and useful extension. If all you ask for is the word of the extension developer that the data won't be used in this fashion, that probably won't change much in practice.