I mean, a judge recently ruled that people can't resell song downloads they buy from online stores like iTMS where as if I buy the CD of the same album I'm free to lend it, sell it, etc.,.
The actual legal issue is called
the First-Sale doctrine
This is US only...basically (I'm not a lawyer) going back to a 1908 case, it was ruled that copyright holders had certain rights, but that they terminated after the first sale of the physical object. Apparently, book publishers and the like back then wanted to control first and subsequent sales. In any event, this did permit resales/used sales of the physical objects, i.e., books, records, CDs, and video games, without interference from the copyright holder or publisher.
I guess left unanswered was the question of non-physical objects...i.e., digital media. Well, with the deep-pockets of corporations like Microsoft, Disney, etc., I don't think used sales really stand a chance in the future.
As an example of changing laws, and consumer rights being diminished, you may be interested in knowing that copyright (for books, films, everything) used to be for only 28 years, subject to a one time renewal. Because some corporations would have died long ago with that rule (I'm thinking of Disney, & Mickey Mouse), they have lobbied and lobbied to continuously lengthen the copyright laws. The last time I checked, copyright holders now own the copyright for "life + 70 years." So, Disney Corp. should be good now until 2030 or so.
That would explain why you can get lotsa old books for free on Project Gutenberg, but nothing recent. And, that also explains why Google was not allowed to post the scans of library books from more recent times on Google books (anymore). You can now only get paragraph long snippets of anything published after the 1940's now. Unless you pay...