The similarity at quick glance will fool a lot of people.
Verisign objected when companies applied for the .cam top level domain. It argued that the string was too similar to .com and would cause confusion. One panelist agreed with Verisign and another didn’t, leading to the ICANN board intervening. Long story short, .cam is now a top level domain with about 4,000 registrations.
So, is .cam confusing with .com? It just was for me.
I was reviewing UDRP decisions on UDRPSearch when I came across a decision for WellsFargo.cam. I didn’t notice the a instead of o in the extension. I figured it was an IDN second level domain that looked really similar to the ASCII version. When I read the decision there was no mention of that, though. It took me about a minute to realize the top level domain.
If this fooled me momentarily, imagine what will happen to the average internet user who gets visits a phishing site that uses .cam?
I think it would be wise for large brands to register their matching .cam domain name for defensive purposes.