At the same time, that site might be creating business opportunities that wouldn't otherwise exist. And almost any business will be dependant, to some extent,

At the same time, that site might be creating business opportunities that wouldn't otherwise exist. And almost any business will be dependant, to some extent, on others. It's a question of how many of your dependencies are irreplaceable, and how likely they are to shut you out. See for example http://en.gentoo-wiki.com/outage-10-08.html http://en.gentoo-wiki.com/outage-10-08.html - they went down and lost all their data because the hosting company had a fight with the people who owned the building where the servers were kept. (Including backups, which made the host irreplaceable - with offsite backups, that wouldn't have been the case.) Building on a site like twitter might increase the risk of being cut off on a whim, but it probably decreases the risk of competitors.