The old reason was because in radio ads, saying the domain with the dash was confusing. A friend of mine just registered a domain name with a made-up spelling

The old reason was because in radio ads, saying the domain with the dash was confusing. A friend of mine just registered a domain name with a made-up spelling of regular words kind of like "leet-speak". The two of us are the only ones who can type it from memory, which is not good.