Hey
I'm not sure if you got the answer to your questions yet.
To find out your reciept number, you need to forward your confirmation email to me at
zach@domainsocial.com. Alternatively, just tell me which email address you used, and I will look up your order.
Keyword Elite is great for finding popular keywords, as well as related keywords. By extension, it's very handy when registering new domains. Before you register a domain, run the keywords through keyword elite and you will get an idea of how popular they are. It also has a dozen other uses.
Brandable domains are domains which could have value when marketed. Google is an example, and so is Yahoo. They don't have much value in themselves, but they lend themselves (because of their structure and sound) to marketing.
Zach