Mike explains that Vista has a tagging component but it is not very prominent. Tag2Find lives in your systems tray, click on it, enter tags and drag in your files, or find files by tag, the larger view also has a tag cloud.
I wonder if you can sort by format, this way I could tag my Outlook emails (but it would be cumbersome to make msg files in order to tag them, I’ll stick to Taglocity.
Eventually in a web office we will have tags for all our documents anyway, again I wonder if these office 2.0 suites have a tag cloud merged with the tags from each product. You could then even choose to merge multiple user clouds.