I think the clip is trying to tell people that they should not post ANYTHING that is personal to them online.Once they post something online without serious consideration,it would be too late by the the time they realised that they shouldn't have done that.Therefore the video emphasise on the importance of thinking carefully what you should upload online.There could be real dangers lurking around u such as stalkers when u revealed personal information on ur blog or the internet..Anyway just think before u post somthing online!