2. The computer-implemented method of claim 1 further comprising: ranking the source categories by the frequency index; wherein the source categories comprise social media and on-line activity.
3. The computer-implemented method of claim 2 wherein selecting the subset of the highest ranked third trending topics comprises: weighting the selection proportionately to the ranking of the source categories, such that the source category with more occurrences in the timeline is allocated more positions in the personalized topics module than a source category with fewer occurrences in the timeline.