I would have thought that the algorithm would be entirely agnostic and based on incoming data only without humans to distort it, e.g. I share details with a doz

I would have thought that the algorithm would be entirely agnostic and based on incoming data only without humans to distort it, e.g. I share details with a dozen friends about aliens landing in Central Park, they then share it on and on. Facebooks algorithm will spot this and also others who did the same and then say "Hey, looks like there is a trend growing about aliens in Central Park" and from there would act upon it based on that data only, e.g. this topic was talked about 5 million times in the last minute and therefore bump it up the list to its corresponding position based on other "trending" topics. Having humans involved will distort that process, thus meaning true trending does not exist. Well, on Facebook at least.