In my opinion, it actually comes down to two main things. The first is the algorithm that TikTok uses to generate your "for you" page (on TikTok this is the ho

In my opinion, it actually comes down to two main things. The first is the algorithm that TikTok uses to generate your "for you" page (on TikTok this is the home page, the first screen you see when opening the app). Vine had a small number of creators that essentially ran the entire app because they had the most followers and views. You only saw videos from people you followed on Vine, or when exploring the popular category sections. For the most part though, the large creators gained too much power after essentially unionizing and demanding salaries from Vine/Twitter. After they left the platform Vine quickly died faster than it already was. On TikTok, there is a massive talent pool and each individual video is tested by the algorithm by sending it out into a test pool of users, and if it does well it continues to get sent to more and more users. This makes it easier to go viral on TikTok than on Vine (on Vine you would have needed followers already for anyone to see the video), which means more people are willing to upload content in an attempt to go viral and this gives TikTok more high-quality videos to serve. It also means that even if the top creators left it wouldn't matter much to the average user; they would mostly see the same feed that they are seeing now. The second is that TikTok provides a lot of editing capabilities in the app itself. Vine never had that. In order to upload edited videos to Vine, there were extra steps involved. TikTok provides these capabilities out of the box with filters, various editing features, green screen effects, etc. It's actually very impressive. One last point is video length. Vine was always limited to 6 seconds (except for at the very end of life when they did a weird feature that allowed a 6-second video to be a preview for a longer video). Vine came out at a time when both Instagram and Snapchat ONLY supported photos, so it naturally rose as the only mobile video platform. During Vine's decline Instagram and Snapchat both introduced video support, allowing for longer length videos (Snapchat at 10 seconds, and Instagram at 1 minute) which only accelerated Vine's decline. People lost interest with Vine, the big creators shifted to Instagram and for sending videos to friends Snapchat became popular. That's been my assessment having lived through the rise of these apps (I was in high school when Vine was at its peak). If anyone notices an error in this, or has other thoughts, let's discuss!