  Rumour detection is hard because the most accurate systems operate
retrospectively, only recognizing rumours once they have collected repeated
signals. By then the rumours might have already spread and caused harm. We
introduce a new category of features based on novelty, tailored to detect
rumours early on. To compensate for the absence of repeated signals, we make
use of news wire as an additional data source. Unconfirmed (novel) information
with respect to the news articles is considered as an indication of rumours.
Additionally we introduce pseudo feedback, which assumes that documents that
are similar to previous rumours, are more likely to also be a rumour.
Comparison with other real-time approaches shows that novelty based features in
conjunction with pseudo feedback perform significantly better, when detecting
rumours instantly after their publication.
