Where is interesting content being posted on the web?

I never thought I'd be interested in a site that hosts documents (I'm talking PDF's, Powerpoint files..), but lately I'm finding that a lot of really interesting content is showing up on sites like SlideShare.
I'm a big proponent of continuing education - and for the post-college work-force world that often means conventions and conferences where people smarter than ourselves are speaking, giving talks, showing presentations. Unfortunately conferences are too expensive, and most of us aren't in a position to have our company fund day or week long conferences (this is a gripe of mine because while the value isn't instantly visible by production, the education aspect, the increased knowledge and motivation from the conference, goes a long way for the duration of your career - not enough emphasis is put on continuing education in the advertising world I live in).
But these days I'm finding great talks and presentations are showing up on sites that I didn't think I'd ever care about. I now follow links to Scribd and Slideshare, and am noticing that the more interesting videos of live presentations are showing up on Viddler, a more feature rich video site than YouTube that allows for in-video notation and higher def video streaming. So my question is, where are you finding smart content lately, where are you reading or watching the things that make you smarter?

My profile on SlideShare (only one document saved so far)
My profile on Viddler (only two clips saved so far)
My profile on Scribd (only one document posted so far)

[update: I'm saving a list of interesting presentations / talks on Del.icio.us here]

Hopefully my saved content on these sites will grow considerably after this posting, 5/25/08. Meanwhile here's the document I posted on Scribd - screenshots of a new ad campaign my client is running in XBox360 - AboveTheInfluence ads streaming via Massive into NBA Live 2008.