ThemBid provides a market where people needing work done broadcast their request and accept bids from people competing for the job. Unlike many of the sites profiled at HighScalability, ThemBid is not in the popular press as often as Paris Hilton. It's not a media darling or a giant of the industry. But what I like is they have a strategy, a point-of-view for building websites and were gracious enough to share very detailed instructions on how to go about building a website. They even delve into actual installation details of the various software packages they use. Anyone can benefit by taking a look at their work.
- Use Munin to tell when to think about upgrading. When your growth trend will soon cross your resources trend, it's time to do something.
- Move MySQL to a separate server. This frees up resources (CPU, disk, memory). What you want to run on this server depend on its capabilities. Maybe run a memcached server on it.
- Move to a distributed memory cache using memcached.
- Add a MySQL master/slave configuration.
- If more webservers are needed us LVS on the front end as a load balancer.