What's actually "defendable" about web startups these days?
rlpb: How about their customers/users or comprehensiveness of data? The biggest thing that stops me moving from Facebook to competitor X is that all my friends are on Facebook and not competitor X. Similarly, would you prefer to use Foursquare with stuff and people already in your city, or competitor Y in which your city is barren?Of course this leaves many startups out, since this doesn't apply to them.