Actually, I love that CMD+SHIFT+) grabs in rich text, but I can grab
something with screwey formatting with CMD+SHIFT+( in plain text.
Sometimes I heart plain text.

I must admit to being slightly confused with your personal taxonomies
issue. DT has excellent (even unparalleled) search, but also storage
in heirarchies as well. Like the filesystem in Mac OS X 10.4, we can
store things in a heirarchical folder structure or do fuzzier searches
as well.

I suppose I see del.icio.us tags as a middle step. It's not as highly
structured as a folder heirarchy, but does provide some structure. It
seems actually less useful in the retrieval-- let's face it, it's a
hassle to page through Merlin's 21 screenfulls of del.icio.us tags.
And alphabetical order tells me nothing about context: how does Amazon
relate to Analog or BBEdit with Begging? Nothing; they're next to each
other simply because of how they're spelled.

Where tags shine is in the creation: I need to remember no paths nor
precedents. If it's about Shakespeare, tag it "Shakespeare." Sure,
maybe you already have "Shakespearean" and "Theater:Shakespeare," but
none of us want to be hassled to consider that fact while we're
creating a document.

Which is, I think, the real beauty of an inbox. Create a file (or a
snippet, or whatnot) and toss it into the inbox. Don't worry about
filing it at all. Later, in a processing step, you can thoughtfully
decide to put the file in the correct location(s). Voila: a taxonomy
which accurately reflects your vision, the context of the item, and
how you're likely to want to retrieve it.

Or am I missing something?

If there's one flaw in DT, I think it's breadth. It does Wiki, but not
nearly as well as VoodooPad. It does outlining, but not nearly as well
as... OK, it is amazingly sucky as an outliner. What's the killer
feature of DT? For me, it's the "See Also..." fuzzy logic stuff. It
helps me see relationships which I otherwise might not see. No, not
every day nor with every document, but it will occasionally make me
say, "Hey.... that's a good point," as if the computer were actually
collaborating with me with actual human intelligence. Kinda spooky, in
fact.

That's the top-drawer, justify-the-expense reason, but the more common
use case for me is as an integrated filesystem and lightweight word
processor. Yes, I have a FS and a word processor (a few of them,
actually) on my computer already, but DT combines them so elegantly
and pleasantly, it makes me happy (and productive) to use it instead.

DEVONthink is a funny app, I think. It's not a killer app; almost
everything it does is replicated in other applications. It is not
simple (else they'd have decent marketing to describe what it does)
nor is its value obvious. But it has wormed its way into my workflow
to make itself the only permanent icon on my Dock. When I find
something I want to save for later, I CMD+SHIFT+) without even
thinking about it.

But back to Emory's other question: does anyone actually use
DEVONagent? What for?