I also suspect that audio-visual content will serve to establish your site as an authority site for search engine purposes.  While I obviously am not privy to Google's search algorithm, I do find that on my own sites, the ones with audio or video tend to climb the search engines faster and go higher than the sites that are purely text.

Now, Google has begun implementation of something called "audio indexing."   According to Google Labs:

Google Audio Indexing is a new technology from Google that allows users to better search and watch videos from various YouTube channels. It uses speech technology to find spoken words inside videos and lets the user jump to the right portion of the video where these words are spoken.

Right now, Google is only using audio indexing on political videos and election related videos.  But I suspect that within the next few months, Google and the other search engines will add audio indexing features to all video and audio content.

If you would like more information about adding audio or video to your web site, please feel free to contact me.

I work with lawyers and other professionals and very few of these service providers use audio or video.  Thus, for the time being at least, you can really stand out by adding video to your site.

My colleague Jay Douglas has been creating professional videos for clients for over ten years and he tells me that a web site video should not last more than 3 or 4 minutes.   Time Magazine columnist Bill Tancer notes that the average YouTube session lasts no more than 20 minutes.

When I videotape and produce videos for law firm clients, I generally limit the segments to one to three minutes.  If I have an hour's worth of information to convey, , I'll create 5 to 7 minute segments and stack them on the web page.  I have seen knowledgeable web developers post 90 minute videos – this makes no sense to me at all.

Columnist Tancer contends that web information consumers are not willing to spend a great deal of time viewing video on a computer or laptop screen.  This does make sense, given that most people consumer video on television, where content (the shows) are broken up by commercial breaks every 7 to 8 minutes and the quality of the video feed can be high definition beamed to a 55" monitor.

So, the bottom line for me: put video on your web site, but keep the segments as short as possible in easily digested chunks.