Documentation pretty well covers the technical aspects, such as the various commands, menu items, views and the like.
When you buy a new car an owners manual comes with it that has lots of bits of information such as how to change a flat tire.
But that owner’s manual doesn’t address questions such as “Where can I go in my car?” or “What can I do with my car?” The answers to both questions would be “just about anything that’s physically possible and legal” – but nowadays people who buy cars generally have preconceived answers based on familiarity. So the owners manual could not, in the first place, list all the possible responses to the two questions; and most car buyers already know the answers, because they are already ‘wired’ into the culture.
General knowledge about computer usage is in on the verge of being ‘wired’ into our culture. Reasonably powerful computers available to individuals have been around for more than a quarter of a century. I consider myself fortunate, because I’ve worked with computer information technology since the 1960s and have had computers in my home for more than a quarter of a century.
The idea of storing notes or documents in a database has been around for a long time. Most of the early attempts required some form of tagging if one was to have any hope of finding anything. Most of the early software could only handle text files.
DEVONthink was the first successful consumer-level document management/information management software for the Mac that combines free-form document management capable of searching across a variety of file types with artificial intelligence assistance for analyzing, comparing and classifying documents based on information content. It continues to occupy that unique niche on the Mac (and I haven’t seen a directly comparable program in the Windows world at the consumer level). The concept of DEVONthink has evolved to the current versions of DEVONthink Pro and DEVONthink Pro Office, and the database design allows scaling of database sizes (especially in conjunction with evolving Mac hardware) to quite large databases. A sister program, DEVONagent, provides artificial intelligence features to assist in searching and filtering information from the Web.
So those questions analogous to the car owner’s, “Where can I go with it?” and “What can I do with it?” become much more open-ended. I’m in my fifth year of using DT databases, and I’m still discovering new approaches and purposes. I can summarize my own uses thusly:
 I use DT Pro/Office to store all of the documents on my computer that ‘interest’ me. I’ve got several topical databases that, between them, manage well over a hundred thousand documents. My databases are very stable, so that I don’t worry about losing information. To make certain of that, I avoid ‘polluting’ my operating system with haxies (such as ShapeShifter), outdated or incompatible plugins and the like; I do routine preventive maintenance on the operating system and the disk directory; and I make backups using Backup Archive and store such backup archives periodically to a different medium in case of hard drive failure.
Note that i don’t use DT Pro as a Finder replacement, nor do I put all of the files on my computers into my databases, as I’ve never found a valid reason to do so.
I’ve found that I can easily define topical database collections that meet my interest and reference needs, and that are still small enough to result in speedy operation on my computers. The ‘bottleneck’ in keeping database operations – especially the artificial intelligence operations and searches – very responsive is physical RAM. For my type of content, if I occasionally prune my main database down to about 23 to 24 million total words I keep it running quickly on my MacBook Pro with 2 GB RAM. My Power Mac G5 dual core with 5 GB RAM can handle larger collections, but I like to keep my databases transportable (self-contained) so that I can run them equally well on my notebook.
By taking this approach I experience search speeds that often take 50 milliseconds or less, and very responsive AI features such as Classify. By comparison, my searches for content are several orders of magnitude faster than Spotlight searches, and of course the search results are displayed in a much richer working environment than Spotlight search results provide.
At the moment my main database has accumulated more than a thousand financial documents. Pretty soon now (before tax time) I’ll export those documents to another database that holds that topical collection and delete them from my main database. I’ll do the same for some other topical information I’ve picked up from Web browsing that will better fit into other databases.
One of these days I wouldn’t be surprised to find myself owning a Mac with 32 GB RAM. But even then I suspect I will find advantages in keeping topically related databases, as in my opinion that improves the performance of artificial intelligence features such as ‘See Also’.
 I call DT Pro/Office the best research assistant I’ve ever had. I make heavy use of the ‘See Also’ and ‘See Selected Text’ features to let me look for relationships of a concept to the information contained in the other documents in my collection. Although some users such as Johnson suggest that ‘See Also’ performs best in a collection of relatively small documents, I find that it also works well in my collections of references, which often include book-length PDFs.
My main database deals with environmental science and technology, environmental policy and problem issues, legal and regulatory matters and development of resources for graduate training. As such it covers many scientific disciplines, law, economics, sociology and the like. But there are relationships between these documents that DT Pro helps me to explore, often giving me insights that I wouldn’t have had without the benefit of ‘See Also’ explorations.
 I use DT Pro/Office as my writing environment when I’m drafting a project, because the information resources are at my fingertips. For example, I can Option-click on a word and see a list of other documents that contain that word. Or I can select a couple of paragraphs I’ve just written and use ‘See Selected Text’ to help me see other documents that are contextually related. I’ve developed habits of creating a new group for such a project that are discussed in other posts in this forum.
So I use that main database as a reference resource, research assistant and writing environment for my professional interests in environmental matters.
I use other databases differently. I’ve got a database that contains more than 20,000 emails that I’ve received or sent over a number of years. I can find messages from or to a person much more quickly, especially about a specific topic, than I could in the original email collections.
At tax time I can pull together all the information I need very quickly from my financial collection, or look at how much money I’ve spent on tree removal in 2006 (a total of $13,500 as the result of a protracted drought and pine beetle infestation).
I’ve got a huge (larger than my main database) collection of information about the Apple Newton, including years of mailing lists and I continue to add to it. One of these days I may add WiFi capability to my Newton 2100 (which I bought in new condition for $200). If I do, I can quickly find the most likely sources for a card and software.
I’ve got a large database resulting from a volunteer project on assessing the impacts of hurricanes Katrina and Rita on the health care infrastructure in Louisiana, and another database dealing with a volunteer project to develop model policy and procedure documents for health care clinics.
And so on. Different databases for different purposes. In each case, DT Pro lets me search, filter and analyze information quickly and efficiently.
My advice to new users continues to be this: start small with an experimental database containing files that are ‘interesting’ for some purpose, and play with it to see what happens. Look at the ‘Academy’ Web site at http://www.devon-technologies.com/support/academy/index.html, and perhaps download and play with some of the example databases.