For a small website, there is no real practical, cost-effective reason to store data on a different server than your website. As your website grows, however, it may become more useful and even advisable, especially if you deal with large amounts of unstructured data (i.e. big data). One solution is to use a cloud storage system for data storage and retrieval.
Many large cloud storage vendors will offer affordable storage options and per-transfer prices for retrieval. They also have massive infrastructure that provides you with scalability and in some cases, redundancy. They may also offer service-level agreements (SLA) to ensure that you receive at least the amount of uptime that their service guarantees.
While many companies now use cloud storage for backup and archiving, it is a bit more involved to connect a live website to a cloud-based database storage location. You will need to make sure that you get the most for your money and are not wasting valuable bandwidth with inefficient practices. That may mean making full use of data caching, limiting the number of requests necessary to complete user-initiated transactions, and developing sound code that keeps the data flowing and does not bog down your server.
While the advantages of cloud storage are apparent, there are some disadvantages. The very well-publicized outages of certain cloud providers is one such example. You are essentially leaving your website and possibly your business in the hands of strangers. For larger files and transfers, it may become too costly to use cloud storage. Another possible disadvantage is privacy. With growing concerns of government spying, you really have no way of knowing if a large corporate cloud provider is turning over your users’ private information to third parties.
Above all, cloud storage is generally a good idea for saving money and possibly increasing local security (since data is stored off-site). Taking it beyond backup and archival and actually using it for daily data storage and retrieval can be risky, however, and you will ultimately have to decide if the benefits outweigh the risks.