I think this is good concept - though I'm not sure if I would take it to the levels that they did (the Facebook part was a bit much for me...).

Even a small thing - a personalized postcard in the mail that arrives a few days before you start - would make me smile and feel welcomed.

There is a fine line though, and the difficulty is that the line is different for every person. Some people would love a personalized cake celebrating their first day, others would not.