I really, REALLY need you to answer this question, and not shy away from it.
What is the difference between a library (city, county or school) that offers access of copyrighted works to the general public, and an individual who uploads copyrighted works to the internet for the general public? In both cases, the original work was paid for once, but later enjoyed by many without compensation to the original creators. How is the one okay, and not the other?
Libraries purchase a finite number of copies–even of digital works. Borrowers borrow the work and at some point they return it. If they want to have the work in their collection permanently–they have to buy it. Thus libraries can be a form of marketing. Many authors and artists like to have their material in the library for this reason. Publishers generally strive to get their books into the magazines like Publisher’s Weekly that librarians use to make purchasing decisions.
Bootleg copies are different. Someone who does not care about the law or their own integrity could make a copy and share it on the Internet resulting in innumerable copies. So IF your question was an attempt to rationalize illegally copying CDs, movies etc, remember to rationalize means to bring your standards down to meet your actions. Don’t do it.
The Golden Rule also applies here. If you were an author or artist, how would you want your work treated?
As an individual, you are welcome to lend your books/CDs/movies to friends, family, even strangers if you wish. There is nothing prohibiting that.