Most of them are real, but it is possible that some scammers take advantage of loopholes to make false propaganda. I have encountered a fake online store that sells diet pills. It cannot be found on Taobao, but they made a fake webpage. When you click on it, you will see tens of thousands of good reviews, but they are all fake. So you must have your own ability to distinguish when watching advertisements, and don't be cheated by scammers.