Friendster is actually in decent shape today. So inability to scale didn't kill them--it just dealt them a very substantial blow.

Twitter would be an example of a startup that experienced severe scaling issues and still ended up on top.

Know any others?

I remember the early days when you couldn't log in to Friendster for hours because the servers were overloaded!

Did they attribute their performance problems to tech stack or architecture? Or did they ever say?