All the time. I think about this stuff for every new feature that needs implemented server-side. Our system is very read-heavy(posts need to be circulated int

All the time. I think about this stuff for every new feature that needs implemented server-side. Our system is very read-heavy(posts need to be circulated into different feeds for users), and all the mysql joins were starting to slow things down. We ended up using redis sets to store post_ids for specific feeds, it speeded things up considerably.