That is an overly simplistic problem description. It's trying to identify spam/abuse in a universal way, which is a much harder (and barely coherent) problem,

That is an overly simplistic problem description. It's trying to identify spam/abuse in a universal way, which is a much harder (and barely coherent) problem, and then delete those tweets which makes the cost of a false positive much higher. What’s far more feasible is to compute the probability a given user would like to see a specific tweet, and then have those below a certain threshold hidden (IE, don’t ping the notification tab for it). This is actually a very well-studied problem, and the massively parallel ML infrastructure it would take exists. Eg, http://www.datanami.com/2014/07/17/inside-sibyl-googles-massively-parallel-machine-learning-platform/ http://www.datanami.com/2014/07/17/inside-sibyl-googles-mass...