For this article, the focus is going to be on the WIPO treaties and the library exceptions. These are not the only provisions relevant to creators and other provisions may be addressed at a later date.
The WIPO treaties provide for some key rights to Copyright holders. If a Copyright is registered in the United States, it can then be registered in other countries through this treaty. The same can occur the other way, allowing for validly registered Copyrights in other countries to qualify and be granted Copyright Protection in the United States. Further, the WIPO treaties standardized Copyright durations. Specifically, the United States had a formality requiring the Copyright holder to renew the Copyright. Failure to do so would move the work into the public domain. The WIPO treaties restored the Copyright to such works when the work was still protected in the country of origin, provided the country of origin was not the United States.
As for the libraries, the law was amended to address the number of internal copies a library could hold. These are not necessarily the copies loaned out by the library, but instead the copies held for the purposes of preservation and interlibrary loans. It also allows the library to continually modify existing digital copies into new formats, as prior formats become obsolete.
This is a fraction of what the DMCA provides.For example, the provisions of the DMCA effect how search engines operate and when certain videos are removed from websites. The WIPO treaty directly expands the rights of Copyright creators. In the future, there may be more articles on the DMCA to explain the remaining provisions.