I did all the programming for BCC. I am not sure what you are specifically referring to with "syncing", but the code to all features discussed in this writeup is only a few hundred lines. Aside from having to put an HTTP client in my Java app it is fairly painless.
I think you answered my question. By syncing I meant that, for instance, when a customer makes a purchase, a whole chain of events unfolds (databases are updated, keys are sent out, analytics packages are updated).
Yeah, I originally did all of that via ejunkie and now it is all custom except for e-junkie wrapping the underlying API call. Back when HTML in notepad was the extent of my programming skill, having ejunkie keep stats and then hand updating a spreadsheet every month made sense. Now that I'm comfortable in Rails it is really easy to automate bookkeeping tasks like that.
It wasn't clear to me from the article, but it seems that a lot of the 'syncing' of information between databases and services was programmed by hand by you. How much time did you spend on this and if you had to re-setup your infrastructure, would you go with a service that does most of this for you (if one even exists)?