In my case, I am liable to name a few noirs that were the earliest ones I ever saw that, at the same time, were memorably satisfying to me in some way. For example, I'd rate The Big Sleep highly on that score, of making an impression because of some satisfying factor combined with earliness of my seeing it in my life. Another one like that for me would be The Asphalt Jungle. Another would be The Maltese Falcon. I would have seen these early on either on tv or in a revival.
Top 10, in my case, would depend on impressions, satisfactions, and when I saw it, which would depend in turn on a number of factors. Some would depend on seeing posters at the time of release, even if I only saw the film years later. The advertising alone combined with finally seeing the picture would have an impact effect.
I'm saying that for me the idea of top 10 isn't necessarily something haveing to do with objective quality or critical ideas of quality. I saw The Killing early on, but not The Big Heat. This would affect my disposition toward these films.
If BB and Twitter users are picking out the same films generally, what does it mean? It may mean only that publicity, time of viewing, age of viewers and other such factors are somewhat congruent for the two samples.