  Social media information distributes in different Online Social Networks
(OSNs). This paper addresses the problem integrating the cross-OSN information
to facilitate an immersive social media search experience. We exploit hashtag,
which is widely used to annotate and organize multi-modal items in different
OSNs, as the bridge for information aggregation and organization. A three-stage
solution framework is proposed for hashtag representation, clustering and
demonstration. Given an event query, the related items from three OSNs,
Twitter, Flickr and YouTube, are organized in cluster-hashtag-item hierarchy
for display. The effectiveness of the proposed solution is validated by
qualitative and quantitative experiments on hundreds of trending event queries.
