This is not going to work if everyone releases one, but being early-to-market with a Google Earth-themed widget still warrants a mention, especially if it’s goodlooking:

This one is for Mac OS X, and it’s basically just an RSS reader for the Google Sightseeing website — there are no direct links to Google Earth file downloads, instead the widget links to the relevant post on the blog.

(In fact, it turns out Chris Homan made a Yahoo! widget for Google Earth Hacks back in August, which also just lists the latest articles.)

I’m not sure if this kind of widget is going to stay on my screen, as real estate is scarce and there are plenty of RSS feeds to follow.

However, it just occurred to me that the Yahoo! widget engine could be put to some very interesting use, Google Earth-wise, because it can be configured to float widgets above all other windows. This should allow us to bypass the elongated sprawl that my Google Earth Places panel often becomes, to focus on specific content, tidily presented. Why not have small widgets with direct KML content feeds? Here is a great candidate: Tremorskimmer. Clicking on a specific earthquake could — should — bring us there in Google Earth:

Or why not have a widget that rotates random geotagged Flickr photos? Click on the picture, go to the location. This geocaching widget is practically there: Instead of linking to Google Maps, it could link to Google Earth by generating the relevant KML file and having it open in Google Earth.

it would be even nicer, of course, if these widgets could read Google Earth’s current field of view, and return relevant information that you’re interested in — for example return a weather forecast for a spot at the center of your screen. That might be for a future version, but clearly there is a lot of potential here. Widgets could turn out to be the best way to navigate the labyrinthine layers of Google Earth’s panels — and a wonderful opportunity to integrate Google Earth with Google Desktop, perhaps? (And note how ESRI ArcGIS Explorer uses widget-like and tool-bar like objects to keep its GUI user-friendly.)