alt Hacker News> I originally had my tagline as "The Free open-source [Company A] Alternative," which they claimed was illegally driving their traffic to my site.
In the UK it’s common for supermarkets to advertise “we price match Aldi”. (Aldi is the trademarked name of a low price supermarket chain). Maybe the US trademark law is different, but I’d be surprised if you can’t claim to be someone’s competitor.
It also occurs that even if their were laws in the US that said that you couldn’t advertise that you were a competitor of a trademark, they’d probably be unconstitutional.
In the US generally it's "oh hey there do you wanna pay to play charades for a decade with our sadistic jackal lawyers who enjoy nothing less than finding ways to cause pain and bankrupt you so that if you somehow manage to survive financially long enough to prevail in court you will at best enjoy a pyrrhic victory while we shrug off the loss as a rounding error?"