I must say I don't have exact answer right now.
Program data cannot be portable, though it makes a lot sense, as your bookmarks should be different for different computers, I guess, so it might not be a problem.
I am unsure if it would run properly from USB flash (have to test it for that), but it should from USB hard disk.
However, at this point the biggest problem would be licensing, as it is licensed per computer. And I guess it doesn't make sense to license each computer for portable application. I might try some solution so that it is licensed for USB drive, but it requires some work and testing, so I can't say when it might be available or even that it will be available, for now.
But it is a very good idea, thanks for the comment.