Buying bitcoins to sell to someone at a later date for a higher price due to artificially drying up the supply (isn't that squatting too?)
Imagine how dangerous it could potentially be if like Overstock kept 100% of their Bitcoins. Rather than relying on Bitcoin you could potentially be relying on a major corporation. The Bitcoin bid is so thin... if major companies believe in bitcoin I think it would be best if they would sell the coins and supply a "ass end" for bitcoin via fiat on the bid or offering private buys.
I think it artificially inflates the price to a extent as well when people are Bitcoin squatters. I know I don't sleep any easier knowing that so many not really impressive people cyber squat such a large percent, but part of it!
(Mind you I'm all for harder work for more pay rather than demanding people sell their property if they are holding it for profits.)