[HiTech RedNeck]

Alternatively, use of a distributed cache like memcache would probably make a big difference.

Indeed, all user authentication data and the most recent week of posts would probably fit easily in a few gigabytes of RAM. The challenge is how to architect access to it.

[justlurking]

Indeed, all user authentication data and the most recent week of posts would probably fit easily in a few gigabytes of RAM. The challenge is how to architect access to it.

Memcache is relatively easy to use as a layer between the application layer and the database layer. That's not the most efficient implementation, but it's not a wholesale re-architecture effort.