Glad we could help. SBI!'s tools provide statistics so if you brainstorm for a phrase and it has 0 demand (that means no one ever searches for that phrase) then that's a clear sign you don't want to base your site around that phrase. So while it will never come out and say "Horrible topic" or "You'll never get traffic from this phrase", you can get a pretty good idea once you get comfortable with using the tools.
And just to clarify, SBI! is a great system / guide, but ultimately you are responsible for how much you get out of it. The tools and information are all there but it's up to you to utilize their tutorials, SBI! forums, and not be afraid to step out of the box, get creative, etc.
I say that because I think from my (and others) description of SBI!, a lot of people think it's going to promote your site for you or it's automated to the point that you just tell it what you want to do and it does everything for you. It's never going to come out and say "Don't choose this topic" or "Do X, Y and Z and you will have 100 visitors by next week."
Now there are some automated technical processes such as submitting your site to the important search engines, submitting your Google and yahoo sitemaps (a list of all the pages on your site so the engines know about them) But as far as choosing your topic, marketing, making money, writing content, etc. you are ultimately in control of your own destiny. SBI! provides the tools, tutorials and guidance in such a way that I've never seen before with other systems. That's why I push it so heavily for beginners. It ensures you understand how and why websites succeed (and fail) before you even start.
Not everyone needs that kind of guidance. There are numerous people on this forum who are doing fine without using SBI!. But if you like structure and want a guide to walk you along the process then it's a good option.
Also check out
http://videotour.sitesell.com and
http://demo.sitesell.com The tour will show you how it works and the demo will actually let you download the action guide you get when you order.