I have a really good idea for a social networking website, I am?
My advice to you, quite simply, is to let someone else deal with it. The level of abstraction we can work at right now as developers/software entrepreneurs is quite extraordinary, taking advantage of this will let you focus on core business functionality when it matters most. Taking traffic and storage as the example in your case, Microsoft Azure can load balance your web servers at a click of a button, even automatically spin up new instances as load increases. Storage space, geo redundancy is also handled for you as part of their platform offering. SQL databases are provided at the database level, in other words server and instance maintenance, and clustering is managed for you further freeing up your time to focus on your core. As a side note you mention a limit on SQL storage, to reduce risk of reaching a limit quickly and just as advice in general you should probably move image and document files off the database and onto blob storage. Itll save you a few quid too. Perhaps you might like to look at 3rd party storage providers for your underlying framework to save you having to worry too much about that as well!