For me, ironically, as it grows it is also starting to lose its lustre through mass adoption leading to lower quality and fewer connections... connectivity activity diluted? new joiners not so interested in engaging as observing? new joiners just joining because everyone else in their school/college is (...and YouNoodle just want mass membership)?
Hence the fact I am getting bored of it but that, however, seems to be true with most sites after the new-and-shiny phase passes.
Web communities are great and all that, but as I get older (sound like an old man even though I am a twenty-something) I actually want to meet people, network, and have deeper more meaningful engagements (...ok ...real-world fun & parties ;) ).