The sign of a healthy - or perhaps frothy - industry is when conferences start to see strong attendance and/or exhibitors willing to pay through the nose to set up a booth. At adtech earlier this week in New York, the place was jam-packed after more than 12,000 people pre-registered for the online advertising conference. Going through the four floors of exhibitors was like a work out as you struggled get from booth to booth. Meanwhile, the Web 2.0 Summit was a sell-out despite tickets costing $3,000 (see Richard MacManus' round-up post). Obviously, the conference industry is cyclical with attendance soaring when companies are feeling bullish enough to cough up a few thousand dollars to send employees away for a few days; and falling when marketing and travel budgets are pinched. One of the consistent challenges facing conference organizers when things are going well or badly is making sure the content is engaging even though many people attend for business networking opportunities. To be honest, adtech's programming was disappointing. There were a few interesting sessions (a user-generated content panel featuring Ze Frank; and a future of advertising panel with Ted McConnell, Interactive Innovation Director with P&G) but many others were less-than inspiring (the format featuring at least four panelists didn't lend itself to a good conversation). As we start to put together the mesh '07 conference, the focus is making sure we feature people, panels and work-shops that are engaging, stimulating and, well, interesting. Like other conference organizers, there is pressure to live up to peoples' expectations. This is particularly evident during the good times when there's more competition to attract attendees, speakers, advertisers and exhibitors.