Website uptime is the amount of time your website is “up” and accessible and functional for users. It’s a business-metric, because having good uptime and response time improves productivity and profits.
Having a consistent and reliable website strengthens your online presence, reflects well on your business and can also help increase profits – especially if you have an in-site shopping function that needs to be dependable. No website has 100% uptime (99.9% uptime is about 9 hours of downtime a year), but having your website up as much as possible should always be a priority.