Whenever I do a demonstration I always field the question on how these products compare.  In my opinion, Quickr and Quickplace represent collaboration tools. They allow you to post information, either as pages or in files, where other people can get at it. When Quickplace first appeared the creation and editing was quick and in this regard it was somewhat unique. As a way to quickly generate a purpose built web site, I was probably one of its bigger fans.  

Now there are numerous products, many open source, that have many more look and feel options, are easier to use and navigate, and are in fact quicker for this purpose.  Quickplace has morphed into Quickr, with the ability to connect into other products in the Lotus inventory, but it retains many of the Quickplace characteristics.   It is NOT a document management system in the same way that Sharepoint is not a document management system. Workflow is limited, version control is limited, and if you want it to do something that it cannot you get to work through an API vs Domino Designer.    

DomDoc was full blown (note the past tense) in terms of document management. It grew over a long period of time and the functionality was very deep, however, people found the UI to be lacking.  Docova originally started off as a demo of our Domino Web Development tool kits to show how you could create a compelling user interface, and the document management context was influenced by DomDoc.

While helping clients build their applications we found they were not using all of the functionality in the toolkits to make a clean and functional user interface.  The positive reaction to the demo prompted us to finish the application. It has many of the features you would find in a full blown document management product, still runs on the Domino back end, allows you to use the Designer Client to add functionality but has a user interface that is much more like a typical Windows application than what you would find in a browser.