Hmmm... PBO - Inquiring minds want to know what PBO is.... I found:
Portland Baroque Orchestra, Print Buyers Online, Practical Boat Owner, Puzzle Bobble Online - none of which seem to fit this post...

Ahh - it must be Plate Boundary Observatory...??
Here's a site from USGS:
http://volcanoes.usgs.gov/pbo/

Ahh - even better - Check the link below for the Mini PBO Don must be talking about.

Canie

• Mini-Plate Boundary Observatory Project