Google Precipitate

Google Precipitate simply gets Spotlight to index your Google Docs and Google Bookmarks. It does so in the obvious way: bringing down info to a file and setting its "Open With" attribute to "Precipitate", which will launch a web browser in turn.

You'll find Google Docs metadata in /Users/apl/library/Caches/Metadata/Precipitate/com.google.precipitate.GoogleDocsSource. Each document has its own directory and if it is just a simple document, you'll find an XML file within there containing the text of the document. Note that it is NOT a copy of the document; it's only an XML file containing the text. In the case of some files (like Presentations), that might only be author and title. A spreadsheet will have the text and numbers just strung out:

 	<key>kMDItemTextContent</key>
 	<string> Gas & Electric water 12/2007 200.43
 	4/2007 40.67 11/2007 129.28 9/2007 59.07 10/2007 15.78
 	12/2007 115.13 9/2007 92.14 214.87 8/2007 70.61 1812.81
 	7/2007 82.29 6/2007 83.11 Homeowners insurance 667 5/2007
 	136.85 4/2007 159.64 3/2007 206.21 2/2007 228.6 1/2007 193
 	1597.9</string>
 	<key>kMDItemTitle</key>
 	<string>2007 taxes</string>
 

Notice that these files use the same keys that Spotlight and mdfind use.

Right now this only indexes Google Docs and Google Bookmarks; the question many users have immediately asked is "Why not Gmail?" The answer is that Spotlight will already happily do that if you POP your Gmail down to your local machine and doing anything else would be a bit of work. Precipitate's author explains at http://groups.google.com/group/precipitate:

 Supporting Gmail in Precipitate would require building the complete
 receiving side of an email client (plus importer); that's a pretty
 large and complex wheel to re-invent. I'm afraid I'm not interested in
 writing and debug an email client.
 
 If someone were to make a little app that can register to open Mail's
 files and redirect them to the Gmail URL for that message, you could
 set that as the default opener, set up Mail to download your Gmail
 (then set it to auto-launch hidden at login, and ignore it forever),
 and you'd be able to open messages in Gmail from Spotlight. That would
 be a much, much simpler way of getting the same effect.