Forecasting initial popularity of just-uploaded user-generated videos
User-generated videos (UGVs) have dominated contemporary social networking sites (SNSs). Forecasting their popularity is of great relevance to a broad range of online services. All existing studies forecast popularity of UGVs using their popularity statistics that are accumulated for a period of time after they are uploaded. Hence, there is always a substantial time lag (days to weeks) before popularity forecast can take effects. However, such a time lag is undesirable for timely popularity forecast as forecasting initial popularity during UGVs' lifetime is vitally important. In fact, we have found in our measurement that the most popular UGVs usually precede others starting from the beginning days and UGVs generally receive the highest attentions during the first few days. In this paper, we present the first exploration on forecasting initial popularity for UGVs at their uploading moment without accumulating their popularity statistics. Specifically, we first design an effective crawler framework to collect the publicly observable features of videos at their uploading moment. We then collect a representative and large YouTube video data set with 318,627 videos. Based on the data set, we select the most relevant features as predictors and design a neural network-based learning model to forecast initial popularity of just-uploaded UGVs. Experimental results validate the effectiveness of the proposed forecasting model and demonstrate the model's benefits for online services such as in-video advertising and video caching.