In what ways can you bypass a copyrighted image or song in digital form? Can they sue the server owner if the files is compressed,renamed, and separated into 20 pieces?

Do you still have to wait 25 year until the ip becomes public domain? Whats the limitations of fair use?

Does the poor man's copyright hold any water in the real world?

25 years after publishing is for photos
Movies it's 50 yeras after publishing
and for music and books its 70-75 years after the authors death (Depending on where you are)

How the recording is stored doesn't matter much. So yes, the 20 rar files are still considered to be the song.

As I said, depends on where you are: Copyright gets enforced according to the laws of the place where the infringement takes place. For servers it's not where the server is physically located, but where the person is who owns/rents it.
So: look up your countries laws/ask a lawyer. Hope that helped.

I'm not sure about the answer to your question, but I have noticed on youtube and similar sites that copyrighted video is often chopped up into segments that are just under 10 minutes. I've always thought that the reason was because 10 minutes was the maximum one could show of copyrighted work legally, but I'd definitely doublecheck that.

For books, I think debunky is right; I'd always thought it was 75 years after the author's death, but that's probably the number here in Canada. If memory serves, in school they told me that something like 20 pages of a work can be copied legally; there was a sign by some of the photocopiers in school that stated the number. (it was different for works smaller than a certain amount, though, some percentage I think; otherwise you could just rip any full work smaller than that)

But yeah, I'd definitely look it up if you need to know this, because it varies depending on location, and I'm not 100% sure about the numbers I said, other than the 75 one.

Originally posted by DragonsDemesne
I'm not sure about the answer to your question, but I have noticed on youtube and similar sites that copyrighted video is often chopped up into segments that are just under 10 minutes. I've always thought that the reason was because 10 minutes was the maximum one could show of copyrighted work legally, but I'd definitely doublecheck that.

I think that was a technical limitation from the early days of YouTube before Google bought them, more than anything else.

There are no codified specifications of "fair use" in the US. Every case is handled differently.