Google’s approach to scalable engineering

Conway's Law: "organizations which design systems ... are constrained to produce designs which are copies of the communication structures of these organizations."

If you create a corporate culture that encourages developers to talk to anyone in the company to get their job done, regardless of orgchart, you get a system that re-uses other systems whenever appropriate.

There're some downsides too: if anyone can talk to anybody, then the software starts looking like everyone's been talking to everyone. This leads to some real WTF dependencies, eg. why does websearch depend upon GMail?

I actually find that tying aspect pretty annoying, especially as it relates to Google Groups. Yahoo Groups makes it much easier to subscribe to Yahoo lists with non-Yahoo email addresses and manage the subscriptions and what goes to which address from a control panel. With Google Groups, I had to make a separate Google Account for my .edu email address just so I could subscribe to a GG mailing list with it, so now I'm juggling multiple Google Accounts.