Eric - sorry it has taken me so long to give you feedback.
I have to admit that I was put-off by the length of Ryan's plugs. I timed him, and it was well over 10 minutes before we got to anything beyond an advertisement. I don't mind the plugs, but I would suggest he limit his time spent doing that for future webinars to 2 minutes or less. Both Christine and I had a hard time listening to your opening because we were so put-off by the infomercial.
It was good to see foursquare being acknowledged with a webinar. I agreed with everything you said, and recognize location-based "social medias" as potential advertising platforms. They are far from main-stream, but they're good for building fans and buzz.
Recently, I had a long conversation with my dad who is working to help promote a local concert venue. They get bands like The Who, Stone Temple Pilots, and Ringo Starr - these shows are easy to sell tickets for. However, it is a struggle to get some of the lesser-known shows promoted because the regular ticket sales media channels are so dead: radio, newspaper, and TV. TicketMaster's website is the strongest one that is left, but they only promote their own stuff. How do you find out what concerts are coming?
We talked about facebook, SEM, MySpace, and even iPhone apps ads. When you put all of this together you reach an audience the size of say what the radio used to reach, but it is very hard to track exactly which medium did what. It got me thinking about the true difficulties of advertising today. There is really no way to know what triggered a customer to seek out your brand. So, foursquare becomes another arrow in a larger quiver of numerous advertising medias. Except your bow doesn't shoot one arrow at a time - it is a machine gun. In order to reach your old audiences, you have to blanket the world in your arrows knowing that most won't hit, but the few that do need to go straight for the kill.
Webinars like this, very media-specific (talking about just one arrow) are so valuable today. You did a great job helping people understand how to use foursquare. It would be great if you continued the series: Google Buzz, Whrrl, Yelp!, etc. People need to know how to aim each arrow for the kill.