Though Mekentosj’s Papers application can be considered a reference manager, allowing you to cite research sources and format a bibliography, its greatest strength is its use as an online system to help you effectively manage research collections.
Papers 3 for Mac, Windows and iOS now includes a new collaborative feature, Papers Online. Papers Online introduces two features: Shared Collections and the Reading List. Shared Collections are collections of papers that are stored online and can be accessed and edited by multiple people. Only metadata are shared, but Papers will allow you to download and save PDFs for the documents as it usually does. The reading list gives you several new ways to more easily get articles in and out of Papers and keep track of what you are currently researching.
For more general information about Papers 3 view this online video.