Great list Matt, thanks for sharing. One test I now use is this: Is the core feature, without any additions, enough to cater to a big market? I've noticed that

Great list Matt, thanks for sharing. One test I now use is this: Is the core feature, without any additions, enough to cater to a big market? I've noticed that some of the best startups solve one really important problem and are able to ride that for a long time. Examples include Google, Dropbox, Facebook, and now Stripe. If no one gets really excited when you show them the most basic version of your idea, then padding it with more features is probably not going to help.