Grammarly sends up to 10k DNS requests to it's servers every day. That's 380 requests per hour! or 6.3 requests per minute! Queries servers are grammarly.io, grammarly.com, grammarlyaws.com.
Why would they do that?? Why would grammarly addon ask for IP of mothership server so often? Uninstalling this.

UNABLE TO GET GRAMMARLY ON FACEBOOK.

It is wrong more often than correct. It works halfway decent on spelling, but grammar is wrong most of the time.

I thought that this was a great grammar tool, but when I Started watching a video, The video would just not appear. And when I removed Grammarly, The video worked absolutely fine. I was not signed in, so My guess is that If you don't sign up/in, they will break the website you are on.

When it works it works very well. About one half the time it signs it's self out. Doesn't pick up mistakes on Facebook. Adds commas where they don't belong.