FB tried this with "poke" (remember that) and that didn't work so well. A service with a number of users is not as easy to copy as it would seem. Replicating th

FB tried this with "poke" (remember that) and that didn't work so well. A service with a number of users is not as easy to copy as it would seem. Replicating the technology is one thing, getting all the users is another.