I was just wondering where people get the impression of some technology being "hot" and on everyone's lips? I mean, some people tout how Ruby on Rails is so popular and everything, but I don't recall seeing any numbers about the relative popularity of web frameworks.

For example, seeing everything through the eyes of, say, del.icio.us is dangerous, because I'd be willing to bet there's a significant bias toward some distinct crowd there. Nevertheless, if you compare, for instance, the number of bookmarks to Ruby on Rails main site, roughly 1900, to those of Django's main site, roughly 1500, there isn't such a great gap. I don't know whether that measures any real aspect of the popularity of the said frameworks, but at least that's a measure of something, instead of hear-say and first impressions.

So how do you measure the amount of positive buzz some technology has?