I like it, and it amused the more suspicious part of me to think that it might just be a way of gathering a database of vulnerable sites without having to put in the effort yourself.
On your "before you scan page", you might want to mention the possibility of a large number of emails, because it can come as a bit of a surprise.
And you might want to limit the number pages on an initial scan because big sites seem to take a hell of a lot longer to process (an I apologise right now for being a bottleneck). I concur with Marketer the possibility of emailed results would be a real benefit.
Is the monthly plan intended to cater to individual sites, or is it aimed at web designers who might be interested in scanning their creations for vulnerabilities? If web designers do feature at all they might appreciate some sort of test data they could print out and hand to clients as evidence of security.
Science fiction is fine it's just going through a bit of a lull at the moment. The current big market is contemporary fantasy aimed at a female readership, and that's where publishers are putting their money, which means there is less to spend on other similar (and I use the word loosely) genres. They are simply going after what sells to the widest audience.
I think sci-fi is also suffering from the decline in interest of the sciences in general. It's a shame but that's the way it is.
Quality rises to the top eventually, it will return.
I'd be interested in email and invites, more than through a social network, give me a little more control over who can see my lists. Multiple lists may well be easier to manage at that point too.