Thinking about users in powers of ten is useful when designing a scalable Internet architecture.<p>Each order-of-magnitude change in the number of users generally requires a redesign of some part of your product's architecture. Don't worry about supporting 10 times as many users as you have now. A design that works for 100 users isn't necessarily the best for when you're supporting 1,000, <i>and vice-versa</i> (a design that works for 10,000 users may be overkill for 1,000 users).