After we write and ship code that probably contains a bug or two (or three), our job is to then write more code, which will also contain bugs. It’s a bad cycle.
This means that someone has to be in the middle, as the face of Flickr, acknowledging these mistakes and going to great lengths to fix things. This is often a thankless job, as users just want their problems to go away and developers (usually) don’t like to be told they messed up. But they do it for the good, and for the love, of the site. Every bug that gets filed and every support case that gets carefully answered makes the site that much better.
After being a liaison between these two worlds long enough, you end up knowing more than anyone else on the team. When you have millions and millions of users that hit every button and link in combinations you would never dream of, then reporting the “interesting” outcomes of their explorations, these support agents become walking encyclopedias of the ins-and-outs of the site and with Flickr, there are odd edge cases waiting on every page. Having people on your team aware of everything the site does is huge. You literally can’t buy that or replace it or outsource it, though it appears that Yahoo thinks it can.