Legal Question in Intellectual Property in Washington

I recall back when I was a teenager just starting out building cars for fun, all the other teenagers would talk about putting a "three quarter cam" in their engines to make them run faster. This "three quarter cam" was ubiquitous. Everyone talked about them. Then one day I went to the local speed shop to ask how much it would cost to buy a three quarter cam. The guy laughed at me and said there was no such thing. It was a myth. That's what's happening here. The "change it 10%" or "change it 50%" is all a myth. There is no such rule.

So here is the real question: Is there a likelihood of confusion between your use of the words and the senior user's. If the mark is distinctive of the senior user's goods, would a consumer reasonably confuse your goods for those of the senior user. That is an incredibly fact-specific question. Sometimes two people can use the exact same mark provided their goods are sufficiently distinct. Other times you can't get anywhere near close to a mark if you are selling a competing product.

For example, do you think I might get in trouble if I started selling a dark, carbonated soft drink in a red can and called it "Coca-Soda"? If you say no, then you clearly need the benefit of advice from a seasoned intellectual property attorney before you get yourself in very, very expensive trouble.