A few years ago Google had launched a very successful email program by using this concept. Before gmail, all one had to do was to go to the website and register to open an account. However for a gmail account, one had to beg, borrow or steal. Some people even auctioned these accounts over the internet.
This sort of scarcity created a maniac rush amongst the google fans. People who had a surplus invite thought they were gifted and told the entire world how great their gift was. Hence increase the desire and perceived value of the email service. While those who were unfortunate enough not to have a gmail invite thought that they were missing the party. In their desperation they flooded the inbox with requests. Everyone wants to be a member of an exclusive club. This club derives its importance not from how good/bad the product is but from how long is the queue of the people trying to get in.
Google wave might be a better product than Gmail (although I could never understand how to use it), but this same marketing launch scheme that banked on Scarcity Premium failed terribly. Nobody seems to care about a wave invite and everybody seems to have a couple of them lying idle. I guess the hardest thing is business is to repeat one’s stellar performance.