All of the features available in PDF documents are made available through this program. Linking to various types of objects (PDF-documents, images, movies and sounds, intra-document-links, web-links), generating forms for user input, creating PDF documents from scanned images, making whole documents searchable through an index, etc.
About the only drawback is that there is no alternative to this program, so one has to use it for editing PDF documents. And if one's platform of choice tends to be Unix, this is a very expensive choice.