As social media become increasingly popular, more and more people express their opinions on news, products, and movies in online social networking services such as forums, discussion groups, and microblogs. Given a popular Web document containing a couple of important subtopics, it can attract intensive social discussions (e.g., comments). It would be interesting to align the social discussions with the subtopic contained in the Web document. It is obviously impossible to manually align them, due to the huge volume of social content. In this paper, we propose a novel framework that can be used to automatically detect the subtopics from the Web document as well as align the associated social discussions with the detected subtopics. This provides a new view of the Web "standard" document and its associated social content through top ics, which facilitates the readers to quickly focus on those "hot" topics or topics that they are interested in. Extensive experimental results show that our proposed framework significantly outperforms the existing state-of-the-art methods in social content alignment.