I agree that slide decks suck as a sharing medium (unless you go to the trouble of adding "notes" under each slide, and share that, but then you're better off sharing a different document). Martin Fowler puts it very well in this post: http://martinfowler.com/bliki/Slideument.html
I can see how sharing a slide deck would dilute the value of a talk. At the same time, sharing my slides lets me reach more people. They might learn more by watching the talk, but it's a trade-off.
There's also the question of the legality of sharing these slides on websites such as InfoQ or Parleys, where the slides are synchronized with the video. But I guess option (c) could work for these.
http://www.infoq.com/presentations/Are-We-There-Yet-Rich-Hic... http://www.parleys.com/#st=5&id=2103&sl=2