I've had quite the opposite experience. I've made maybe 20 real life friends that I met first on the internet (primarily Twitter) and almost all of them have proven to be at least as funny intelligent and likeable as online. Almost all of them I now just try to interact with IRL vs online.

I've never encountered this issue of expecting this cool person based on a manufactured illusion and then finding them to be mundane. And I know without the internet I might have more of a sense of community in general but I don't think I would have found people as unique and weirdly on my wavelength.