Interesting post by Techcrunch and Erik Schnofeld today about the widget world and how tracking within this space is difficult. The trouble is that: 1) there isn't a standard widget format / type - Widgetbox, for example, offers both javascript and flash versions of widgets.

2) many widgets use multiple services for installers, analytics, etc - causing double counting among some providers.

3) it's a new, quickly growing frontier (which always presents challenges). This will get clearer over time.

Who rules the world of widgets? It is difficult to measure, but comScore takes a stab at it with a new ranking of widget providers as measured by viewing audience... It seems like Meebo should be in there, with a reach of about 19 million, which would put it right after iGoogle. Who else is missing?...

Erik then updated the post with the following message (kudos for doing so):

Update: WidgetBox claims 25 million monthly uniques for their widgets, but says they don’t all get counted by comScore because they use Javascript. Another problem with this list is that there might be double-counting. Clearspring, for instance, puts a tracking embed code in RockYou’s widgets. Like I said, these things are difficult to measure.

Full Comscore release is here. Update: VentureBeat has now covered the Comscore data but without much mention of tracking complexities.