I can't say enough about Tagger
I’ve been increasingly using the OpenMeta system for helping to tag my documents. I began to adopt this after revising, yet again, my PDF workflow to rely on DevonThink instead of other applications I had used previously.
I have to say — the Tagger application by Ali Rantakari is simply a low-friction application that does one thing, and does it well. With a few keystrokes (via Spotlight), Tagger is open and allows me to instantly tag the current document in almost every application I use.
I can then use these tags with Spotlight to locate the files I am interested in, or use those same tags to help organize my DevonThink database. A “ToRead” tag helps me keep track of which articles I need to review for my next project.
I am duly impressed.