JACKWEB  I agree with JMAX, auto tagging doesn't seem to work. I thought it would actually search through for words within the currently selected document?? But it gives me random words which have nothing to do with the pdf I'm looking at? :(  (Version 1.7.6)

KEYBORED  What was a pleasing novelty when it first emerged has become an indispensable program to those of us warehousing any significant number of PDFs in the chaos of folder hierarchies. It's especially useful for those of us who find or make our PDFs serendipitously in the middle of doing something else (and therefore can't always file them precisely and wisely), or for whom a PDF saved appropriately for one purpose becomes relevant to another one later on. Such is the life of writers, researchers, teachers, among others. For us, YEP has become the gateway to the riches buried in our HDs. Those who can remember everything without ever forgetting don't need it, of course. I do.  (Version 1.7.5)

JMAX  I find Yep pretty buggy:

1. Unless I remember not to touch the name of the pdf while I'm tagging it, the tags won't be saved, and there's no warning to tell me this is happening - you just have to notice the doc is still in the "untagged" folder. If you're working quickly to get through a whole bunch at once, it can be pretty frustrating to look up and see some of them have to be done again.

2. Same thing's true when some tags get mysteriously combined into one, like "mac" and "camera" might be combined into a "mac camera" tag, which is worthless, and you have to go back and do it again.

3. There's the "auto-tag" function, which often doesn't work at all. That might be the good news, as when it does, a giant pile of mostly irrelevant tags gets dumped into the file. I suppose it doesn't really hurt anything, since you don't see the metadata later, but it's pretty weird and you wind up having to input the correct tags anyway.

4. Finally, the ability to select non-contiguous files by holding down the command key often doesn't work, and instead results in the prompt to the user: "are you sure you want to combine these PDF's?". Uh, no, actually, I just want to tag them the same way.

By the way, I've tried uninstalling and starting over, with the same results.  (Version 1.7.5)

LEV  TexLogic - I originally took issue with Mendota (see my post above) but once he explained his thinking about caches and the naive user, I realise he has a very good point.

Your comment about it being the user's responsibility is fine but it assumes an ideal world. In the real world, there are lots of users who are barely potty-trained enough to get by, and apps that can help them will do better (and are more responsible IT citizens) than libertarian apps which just say "Don't whine if you get hosed". You might argue that Spotlight is redundant because it's the user's job to make sure that his/her files are consistently named and stored in a logical directory structure. Now tell Grandma when she can't find the first draft of her part-time PhD thesis...  (Version 1.7.4)