Here's a podcast for anybody wanting to understand the basics of developing an on-line community or social networking or web 2.0 application. Covers both technical, rss and tagging, and the social aspects, trust and participation.
From Knowledge at Wharton, Podcast: What Makes an Online Community Tick? Ask Craigslist, Yahoo and Pheedo. (registration required)
"On-line communities, [social networks and web 2.0 applications] have become not just a major social force, but a significant driver of business activity both online and offline. Facilitating, nurturing and benefiting from those communities, however, is not a simple task. To explore what makes these communities tick, Kevin Werbach, a professor of legal studies and business ethics at Wharton, spoke with Craig Newmark, founder of Craigslist.com, Julie Herendeen, vice president of Network Products at Yahoo and William Flitter, CEO of Pheedo. All three are involved with successful online communities and efforts to leverage and facilitate online communities, but in very different ways."