Comment by samspot
A common mistake in accessibility is to assume accessibility is mostly for users who are blind. I've rarely seen the opposite approach, calling something accessible that is very much not accessible to a person who is blind. A url is much more accessible for many people with disabilities than the postal mail.
Even if you mean access instead of accessibility, presumably a person who can find a way to acquire stamps can just as easily make it to a library with public computers.
accessibility: the quality of being able to be entered or used by everyone, including people who have a disability