I also agree that it depends on the product or service provided and their resources. It will get my attention but won't necessarily stop me from purchasing. Now, as you may have noticed my grammar also sucks yet I do Technical Writing. I warn the clients up front but they have people that are paid a whole lot less than me to deal with the clean up, they want the content from me.
One example that sticks in my mind was a sign at the entrance to a trailer park in the mountians near our place in Boone ... it read "Trailor Park". I was always laughing when I passed because it seemed so appropriate since it was a run down park in a flood plain near a stream. The last hurricane that went through the area flooded the place and the sign seems to have been washed away ... but it was funny for a few years.
Did ya'll ever think that some people use misspellings of road side signs to draw your attention. I heard that when I was younger, someone one told me it was an eye catching advertisement technique. Now, I ain't saying EVERY misspelling is intentional, but Lord knows I always misspell on purpose - but others... well! :lol: 8)