that's because of the network effect: while you're a small part of people's network, you can be replaced easily. once you've connected 60-90% of their network (

that's because of the network effect: while you're a small part of people's network, you can be replaced easily. once you've connected 60-90% of their network (including the sort of people they follow online, not necessary people they meet in meatspace), you don't need to worry too much about getting replaced.