As you may or may not know, NASA's SkyView service (led by Tom McGlynn) has been extremely helpful to getting WWT running, providing data for over half our surveys. They've put out a heat map showing the most frequently accessed regions of the sky since mid 2007. You can read about it in this Physorg article and view the heat map in the WWT Experimental Community.

Here are a couple of screenshots crossfaded between the green heat map and the DSS.

In the first shot, you can see the plane of the Milky Way and the Large Magellanic Cloud are often accessed on SkyView.

In the second screenshot, you can see often-accessed regions near Orion's Belt, the Pleaides, and the Cone Nebula.  And Sirius too...

Finally, you can also see the footprint of the Sloan Digital Sky Survey.