I'm not a TikTok user, but I'm assuming the recommendation engine is there to keep eyeballs on more ads for longer. Maybe we should be regulating how often and how many ads can be shown on social media, especially to teens and kids.
If it was only network effect, then how did TikTok grow in a space where Instagram and Youtube were already much bigger players? How did they gain that user base?
Network effect helps, but it only explains why they stay big, not how they got big
There really isn't that much making TikTok unique. Yes, their app is well designed. Yes, stitches and video replies make for great social/parasocial features because creators are actually interacting with each other and the community, almost like tumblr. But in my opinion those are reasons number three and two why TikTok is successful. Their recommendation algorithm is number one, by a wide margin.
It also provides different opportunities for growth compared to other social media. A video that gets over half a million views on TikTok may not get 5 thousand on Youtube, or even 10 views on Instagram or Facebook.
It's not just different videos, Tiktok is much better at recommending videos by very small creators and people with no followers. On Instagram or Facebook if you don't already have a large following you most likely wont get any views at all no matter how well your video matches the platform. YouTube often pushes big creators that already made it big while Tiktok allows me to discover new and niche ones.