Words. Pictures. Music. In a nutshell, these are the big three copyright gems that humans generate. Because of the time and creativity it takes to craft these three gems, the creators should have the right to be protected by copyright laws so their work can not be stolen by others. Here is a great cheatsheet of what copyright laws do and do not protect. I realize that not every one wants their work protected. That is why creativecommons.org exists. It allows the creator to share their work, but give others the right to use it under certain circumstances.
The second half of this statement confused me. What does "not be bound by a length restriction" even mean? The word that is confusing to me is length. At first I thought length meant words. But that didn't make any sense. So I'll go out on a limb and say that length is another way of saying years. Reading this Wiki page on Perpetual Copyright confirmed by guess. For example, in the United States, after a creator dies, their work is protected for 70 years. After reading a quote from Jonathan Zittrain, I decided that putting a length of time on copywritten work doesn't make any sense. Here is an excellent map of the copyright lengths for each country.
On the other hand, I have taken full advantage of copyright length. I have read quite a few free books on my Kindle, such as The Complete Tales & Poems of Edgar Allan Poe, thanks to copyright length laws. One argument for copyright length is that it provides a net benefit to society, according to Public Knowledge. However, I believe that taking away copyright protection after a length of time also takes away the protection of the creators' descendants who could benefit financially from their work.