> Haha yeah. In my experience running top internet sites, honestly if you don’t have consistency you probably have a very unskilled engineering team, or you don

> Haha yeah. In my experience running top internet sites, honestly if you don’t have consistency you probably have a very unskilled engineering team, or you don’t need availability either because your company is irrelevant. So Twitter and Facebook must have horrible teams. Both of those if you update your profile it may take minutes (and certainly seconds) until everyone has a copy. When running a site at large scale consistency becomes a business concern. Is it really important to my business that if someone loads a profile 10 seconds after they changed their avatar it is still the old version? The answer is probably "no" and if it is, you can scale a lot larger and on cheaper hardware than if you answer "yes" Hardly any NoSQL database offer consistency or if they do they have eventual consistency as a default. Because for most applications it doesn't matter. Take a blog as another example... if two people hit the homepage the moment after a new article is published does it really matter if one of them still gets the old article? Edit: To try to be helpful... > A good question for someone who doesn’t think consistency is important is: If you have 200 different records that should all be the same but are different due to lack of consistency, which one of those records do you believe? Usually met by blank stares. This is not even remotely what lack of consistency means in the context of distributed systems. In the context of distributed systems they are talking about transactional consistency. I.e. if you hit two servers they each return the same result at that exact moment in time. No one is arguing that the two servers are permanently inconsistent such as in your example just that they are momentarily inconsistent since in a distributed system the cost of consistency is extremely high.