Here is a really interesting slide deck about the eBay software development process and the evolution of their architecture (via Matt from the Trade Me database team):
As I’ve cautioned previously unless you happen to run a really really big website many of the approaches they describe here are probably more interesting than practical.
As far as I can tell from the architecture diagrams included in this deck what we have today at Trade Me is a mixture of their v2 architectures. Those maxed out for them at around 50m registered users, so that would suggest we have some more growth to go before we need to start looking too seriously at what they did in v3.
But, nonetheless, it’s interesting to think ahead to the challenges down the track – for example around the architecture of the application code, and the implementation of search within the database.