It worked flawlessly for years. Sadly, it stopped translating yesterday, and will not translate any language in all three choices!

ImTranslator stills works great, but it requires copying and pasting text to it, then copying and pasting translation back to a conversation.

"Translation Comparison" allowed me to highlight the text to be translated, then right click for the translation, without leaving the conversation.

very good

啟用後會造成眾多網頁異常，像是bookwalker.jp的online reader會變得完全無法使用。

Yes, this is a great tool. But, again: Every time I open up Firefox it keeps naging me to donate with this webpage.
http://imtranslator.net/Translation-Comparison-for-Firefox.asp

update, update, update, update - every time.