Few questions about the alert services


I'm pretty new to this arb-world but started exploring it.
I'm thinking about registering to one of the services (betburger, betslayer, etc.) but wanted to know some info first, info I didn't find in their sites:

1. Do you know how they get their data? they scrape the bookies websites and take the odds from there?
2. They have an alert system by mail/sms?

Thanks a lot!