As far as I can tell, it's just for media (music, movies, documents, etc). There doesn't seem to be any way to move/install apps from your iPad to the external storage.
"I did RC5, but I didn't flush." - Bill Clinton
"I invented distributed computing." - Al Gore
"I had a dream where every American would be free to run SETI@Home!" - Martin Luther King Jr.
"Greendale is a bodaciously small town, Lane... I can't even Find-A-Drug here!" - Charles De Mar (Better Off Dead)
"I did not have BOINC relations with that woman, Rosetta@Home!" - Bill Clinton