This is very regional.
.co.xx is common in Britain (.co.uk), Japan (.co.jp), New Zealand (.co.nz) and probably others. It's perfectly legitimate for a site linked to those countries.
.co.xx is common in Britain (.co.uk), Japan (.co.jp), New Zealand (.co.nz) and probably others. It's perfectly legitimate for a site linked to those countries.
My suspicion is that it was due to abuse; a long time ago, I noticed some university had registered IIRC .co.br (our correct equivalent to the .com gTLD is .com.br; this is a notable exception to the assertion above that "I rarely find a reputable business that is using anything but .com or .co.XX as the primary domain", since plenty of reputable businesses use .com.br as their primary domain, not .co.br which doesn't exist).