Why do you need my Betfair username?
When you register as a Bet Angel customer we have to permission your account to be used with your chosen exchange. For that to happen we have to submit your username to the exchange. If we don't do this you will be unable to use Bet Angel. We also need some way of tracking your usage so we license the software by your username, not by installation. This means you can install multiple copies of the software on multiple computers without requiring additional licenses.