Your tags are saved to the meta-data contained in the media file. They are not stored in the iTunes library.

You can create playlists based on your tags by creating iTunes "Smart Playlists" that use the "contains" filter on the Comment field. For more info on how to create smart playlists see the iTunes help.

It's easy! At any point while a song is playing in iTunes you can either click the Tweet icon in the task-tray or press control-alt-enter. This will bring up the Tweet tag window where you can edit your list of tags.

Tweet is free. That's right, free.

When you first install and run Tweet your tag clouds might display all manner of nonesense. There's nothing wrong, it just means that some of the tracks in your music library already have text in their Comment field. Tweet builds the tag clouds from the contents of the Comment field so anything that's there already will get picked up. If you're feeling brave I have a script that will wipe out the contents of the Comment field for all the tracks in your library. But be forwarned, this is a destructive and irreversible operation. If you're afraid you might wipe out something valuable you're probably better off just manually cleaning up the Comment fields manually. If you're feeling brave let me know and I'll set you up with a copy of the script.

Tweet is free so there's no team of highly-trained geeks waiting by the phone for you to call customer support. However, I will be happy to try and sort out any issues you're having. Just drop me a note and explain your problem. I'll get back to you as fast as I can.

Nope, your tags will stay with your music permanently, even if you stop using Tweet or iTunes.

Sure it is. And comments are arbitrary, descriptive strings of text, just like tags. Of course, if you frequently feel compelled to use the Comment field to capture your insightful commentary on the musicological significance of the tambourine part then you probably don't have much need for Tweet.

Meta-data for MP3 files (the notorious ID3 standard) is published. You can get more info on it at http://www.id3.org/. As for the iTunes formats (AAC and ALAC), best I can tell they map to the ID3 fields (more or less). For our purposes they're effectively the same since they have the Comment field.

Just download and run the .msi file. Then follow the on-screen instructions in the setup wizard.

You can un-install from the Add/Remove Programs utility in the Windows Control Panel. If you need more info you can Google "Windows Add Remove Programs".

That's just Tweet indexing and caching your tags. It does this occasionally so that the tag clouds and type-ahead suggestions are kept up to date. You can click on the icon to check on it's progress. You can safely close Tweet and/or shutdown Windows while it's doing this.