In Viral Video Finder, Ad means the video is being promoted with paid distribution by the brand, in most cases through GMV Max. The brand is paying TikTok to push that specific creator video beyond its organic reach.
How to read an Ad label
The promotion applies to the video, not the product by default. Brands usually push videos that are already performing well, proven to convert, or that they simply like. So the views on an Ad video include paid reach, not organic pull alone.
Next steps
More on reading the feed: