The postcards on PostSecret, seeing that they contain secrets, are supposed to be anonymous. The idea behind that is the secret itself should be what you're focusing on.
I think it will be fun to do handwriting analysis on the postcards.
From this past Sunday's post, the postcard with "my Husband and I moved to A smaller house so the kids will __Stop__ Visiting as _MUCH_!" scares me. Not only are the capitals out of place, but considering it's a mom who has kids (and is possibly near/at retirement), her writing is really flowery.
I can't stop thinking about Delores Umbridge and her pink office...