Will they try to compete with storage solutions already in place like STORJ and SIACOIN?
If I am reading their site correctly, do users lend out their hard drive on the SHIFT network so that people can host their websites on another person's hard drive?
Is it possible to offer bandwidth to people that want a significant amount for their website? I know bandwidth is very expensive and if we can decentralize that, that would be a game changer!
Well, technically, they are all storage solutions fighting for the same market of storage providers. However, there are some differences: as far as I know, Sia and Storj don't use IPFS, but have their own protocols, which might make interchanging a little fidgetty.
Secondly, Shift is focussed on storage for websites, which is a very different vector than, say backups or your personal dropbox. Storage providers for Shift will get a lot more traffic, since it's not only you getting some files in and out, but visitors wanting to look at your website.
I'm not sure whether Sia and Storj (or Filecoin, for that matter) are working on webhosting solutions, but this is a very different animal due to traffic. As a provider, you'd need a much more resilient infrastructure, or you'd need way more redundancy in the system as a whole, as well as a good mechanic to prevent some nodes from getting all the traffic and others getting almost none.