Proposition anyone?

I recently received an email from someone asking if I would be interested in adding their online grammar checker to my editing website. I had a good look at the site and tried out the grammar checker (as far as I could go without paying). The only thing that really caught my attention was the homepage text (it's here: http://www.grammarcheck.net/...please note that I don't recommend it!):

...blah blah blah...like many, you’ve likely forgotten much of what you learned. Where does the comma go, for instance? Is ending your sentences with a proposition really that bad a practice?

Hahahahaha... that's pretty funny, but not super smart for a site that specializes in grammar and spell checking. I sent an email and pointed out that I suspect they mean preposition instead of proposition, but I added that the practice of ending a sentence with a proposition might make for a more interesting discussion... ha ha (wink). I didn't get a response, and so far it hasn't been changed. I bet they used their own grammar checker to proofread it.