I LOVE LOVE LOVE SiteSell's SBI! service, and I've used it on and off over the past 10 years, both for personal pet projects and client websites.
But as a WordPress plugin, this one gets a single vote (or zero, if that were possible). I'm even surprised that this was allowed into the official plugin repository!
Don't get me wrong: I know there's tremendous value in the keyword analysis tool, online business building guides, and access to the members-only forum that the free bizxpress lite product offers.
But SiteSell really needs to learn how to be a good corporate citizen an open source community like WordPress.