Simon Belak on the TurboGears list points to The adventures of scaling, Stage 1, an article about scaling a database-intensive reasonably high traffic (~1M page views a day) site based on Ruby on Rails. The author hits upon many of the common topics in scaling LAMP architecture sites. One thing I didn’t see mentioned, probably because it wasn’t particularly relevant for his application, is data partitioning. Any opportunity to break up your database into multiple chunks that can potentially be deployed separately can be a big win in terms of scalability.
The kinds of things they had to do for eins.de is very common in the LAMP stack and certainly applicable to TurboGears users.