I could add one…even though it’s wordy:
Ask 1000 people on the street if they’ve heard of any of the technologies you’re using…Rails? Ajax? RSS? Wiki? API? Tags (the kind that hang off of clothing don’t count)? Ask them if they’ve heard of any of the companies/sites you’re trying to emulate. Digg? Riya? Flickr? Flock? If the universal answer is “Whaa??” then you’re on the right list.