Supremely cool. I've been using languagetool for more than a year, and it slaps! Easy 5 stars.

Incrível, um amigo me recomendou a extensão e com menos de uma semana já adorei :)

Denke dass die guten Bewertungen allgemein zutreffen, ich habe ihn erst heute eingesetzt.

Installed b/c my spellcheck stopped working in Facebook posts.
Almost perfect- Excellent for grammar & spelling.
Even corrects my most repeated error (typing form when I want from, which other spellchecks ignore b/c they are both correct spelling).
However, the way it works by opening a new tab & having to return to comment and then copy/paste, instead of making corrections inside the comment is not ideal.
A pop-up window would be preferable if in comment corrections cannot be done.

I see your response but see no way to reply.
I was trying to use LT in FACEBOOK comments. I did not try it in Twitter yet.. UPDATE: works perfectly after re-install on FB & Twitter-
added a star..

LT is lucid and simple. It does help eliminate errors. Feedback provided by system is clear and robust. Its free tool capabilities are powerful enough to help with sentence correction and accuracy checks.

Excellent et bien foutu polyvalent sur toutes les zones de textes

Easy to use and free

excellent good job