With so many data visualization and analysis tools moving online, the first issue for most developers is how to make it interactive?  This usually comes down to Flash or Silverlight (sometimes Java).  Over at webnhance, they have a great breakdown of all the differences between Flash & Silverlight, coveringf languages supported, Video and Audio codecs implemented, animation theories, and more.

Flash vs. Silverlight: What Suits Your Needs Best? | webnhance.com.