Quick note about Nabaztag, launched in 2005. I found some figures that might be of interest: 50,000 rabbits sold as of June 2006 (Source: Libération) 135,000 rabbits sold as of May 2007 (Source: Le Monde)

It's a pity the figures are only for France, but it gives an interesting picture of how this type of communication objects is sold. Sony sold 200,000 AIBOs worldwide (Source). And yes, I know it's like comparing apples and oranges but it gives a picture of the number of devices out there as well as how things evolve over time.