A friend of mine (pro writer and editor) got a semi-spam email from grammarly.com.
They offered a 15.00 Amazon gift voucher if she would mention their brand on her blog. (One presumes they would want it mentioned in a favorable way.)
She did a google search for the name + complaints and declined.
She disliked that they addressed her by her first name--she's touchy about getting formal introductions first--the bribery aspect, as well as the fact they didn't bother to look up her name on Wikipedia. She's pretty well known in some genres.
She's not at all tempted to try them out. The google search indicated it would be a bad idea.
I thought it might be a good idea to open a thread on them in case others had gotten similar spam.