Running Applications from an External Hard Drive?

[imLOST]

I know that it's not exactly of major concern but I heard that you could run iTunes and other applications straight from an External Hard Drive. Is this true?

I'm in the middle of purchasing a new Macbook with a 120GB HD and although it's big enough for now, I might need to get an external HD sooner or later and the ability to run Applications straight from it is appalling.

Does anyone have any knowledge or this?

 

[iBookG4user]

There are some programs that you can run from an external hard drive and some that you can't. Although instead of putting iTunes on an external hard drive I would suggest putting your iTunes library put on the external hard drive, as that takes up a load more space than iTunes usually. Also keep your movies and pictures on stuff on the external hard drive to save more space. The only thing I really keep on my internal hard drive is programs, everything else goes on my external hard drive.