Though someone else here mentioned how friendster lost their game due to technical debt:
I looked it up and it looks like that indeed it was an issue.
http://highscalability.com/friendster-lost-lead-because-fail...
> "Technical debt reduces uptime, increases bugginess, and makes it harder to fix bugs."
Yes, that is one of my concerns usually. It's good to go fast and build more, but not to an extend where it slows the process down on longer run.