GDesktop and Gmail
Here's where GDesktop starts to show how different it is from the competition.
After indexing the contents of your hard disk, the software begins indexing your Gmail archives. If it tried to do this in one big lump, your internet connection would probably get clogged up, as would Google's servers if thousands of users were all trying to download gigabytes of email simultaneously. So GDesktop goes into what I call "trickle mode," logging into your Gmail account and downloading a little at a time.
Here's how Google describes it:
To avoid monopolizing your computer and internet connection, Google Desktop indexes your Gmail a little at a time when you first enable the feature. After all of your old Gmail has been downloaded, Desktop will almost instantly keep up with your new mail.
It would appear that this is a long process. Google's own known issues list says that downloads of messages from Gmail are done in small batches, two hours apart. And there's no progress indicator. Two days after installing GDesktop, only a fraction of my Gmail messages had been downloaded.
One of GDesktop's smartest tricks is offering offline access to your Gmail messages. When viewing a mail result, clicking the result's title will open a cached copy of that message in your browser window, as shown in Figure 4.
Figure 4. Cached Gmail messages viewed offline
If you'd instead prefer to view the message in Gmail itself (and assuming you have an internet connection), you can click the "View in Gmail" link directly beneath the search result.
This offline searching is one of the biggest things in GDesktop's favor. It means you need be less fussy about making manual backups of your Gmail account(s) (although I wouldn't advise you to abandon them completely), because GDesktop effectively backs everything up for you incrementally. Whether this is an indication of how any future "offline Gmail client" might work is another question entirely, and one that I suspect we won't get any answers to for the time being.
One nice thing you can do with GDesktop is start searching messages in Mail using the same easy-to-type operators available in Gmail. So just type "from:brian" in GDesktop to see all the messages in Mail that were sent from Brian. Same applies to operators like "subject:" and "to:".
In a similar manner, you can use common Google web search operators such as "filetype:pdf" to find just PDF files. Combine with keywords to narrow down the results.
The upshot of this is--in my experience at least--a desktop search that is faster and, better still, easier to use than Spotlight itself.
As you can see in Figure 5, the basic GDesktop results window is very simple.
Figure 5. Results window
It's much simpler than the equivalent Spotlight results window, yet still manages to show a filename, date, path, and contextual snippet for each result. Then again, Spotlight results can be filtered immediately, while GDesktop demands an extra click to open the results in a browser window before you can filter them further.
You'll need to restart your web browser before GDesktop can start monitoring and indexing the web pages you have visited, but once this is in place, it is a very useful and (so far) reliable feature. Because it searches the text of pages you've been to, not just their URLs and title tags, it makes finding specific things easier. All you need to remember is a snippet of text, perhaps just one word, from the page and GDesktop can get you back to it. It goes without saying that this is an improvement on searching through most browser histories.
In addition, search results of cached web pages are displayed with thumbnails, making selection of the right result that much easier (see Figure 6).
Figure 6. Web history thumbnails