Ask HN: What are some bad engineering decisions that screwed startups?

I wouldn't say people fled to MySpace…friendster had this initial surge of users, the site become unreliable (and once you set up an account and got over the initial flurry of fun, there was no "there" there. You could connect to people, you could send messages, but IIRC there was no "timeline" or "newsfeed"). MySpace launched within a few months after Friendster (allegedly inspired by Friendster), had more features, and most importantly didn't crash as nearly as often as Friendster. MySpace also was more "creative" in a GeoCities sort of way, you could tailor your page in a variety of ways, and it appealed to teens (who would go on to create Facebook accounts within a couple of years and shift their loyalties).

Initial Twitter service was built using Ruby on Rails, shifting to Scala on the JVM around 2011-2012. See: https://www.infoq.com/articles/twitter-java-use/ https://carlosbecker.com/posts/twitter-drops-ruby-bullshit/ https://blog.twitter.com/engineering/en_us/a/2011/twitter-se... for a sampling of explanations.