Adobe Acrobat Professional 9.0
Adobe Acrobat is an application that gives you the ability to share a multitude of information with collaborators without requiring them to install multiple programs. Acrobat allows you to gather various files into one or multiple documents called PDFs (Portable Document Format). These PDFs can be viewed with Adobe Reader, which can be downloaded for free on Adobe's website.
PDFs have become very popular because they solve a common compatibility problem. The issue with sharing documents in their original format is that only people who have the application you created them in can view the documents. With Acrobat it is possible to save all of these documents in a format that allows others to view them without needing these individual programs. For example, if the original document was created in a program like inDesign which saves documents in its own unique format, then the only way someone else could view the document is if they also have inDesign installed on their computer. Acrobat allows you to take this unique document and "print" it to a PDF that treats the original like a picture.
Because of the way Acrobat treats documents, it is also an extremely safe way to share personal documents. Acrobat also offers a few security features, useful to business, that ensure the authenticity of the PDF being distributed.