Posted By:
Rob DewolfI'm not a postcard expert by any means, but I do have a lot in my collection. The impression I've always received from postcard collectors and dealers (not necessarily those who focus only on sports) is that postmarks and writing on the backs don't dramatically affect value. If a postmark bleeds through to the front, then yes, that's a problem. But typical usage isn't a big factor.
This doesn't take into account PCs slabbed by the all-knowing grading companies, who, as it has been pointed out here, have deemed writing and postmarks to be cause for severe downgrading.
Like others have said, I like postmarks and content on a PC. I think it adds to the collectabilty, if not the value.