Practically every "trending" algorithm involves some degree of manual tweaking. Otherwise, they end up prone to identifying uninteresting trends (like the curre

Practically every "trending" algorithm involves some degree of manual tweaking. Otherwise, they end up prone to identifying uninteresting trends (like the current day of the week, or other time-sensitive trends like "lunch" showing up around local noon), or are easily manipulated by groups of users. Besides, one of the features of Twitter's Trends is a prose description of what the keyword references -- there's no way that could be generated automatically.