EcomExpo is a virtual conference. You can attend from anywhere with a high speed connection. Everything is done online so there are no travel expenses or hotel expenses like a regular conference.
As an attendee at Ecomexpo in Febuary 2005, I was quite satisfied with conference in general. There were lots of affiliates there, as well as Exhibitors. It really does "feel" like a true conference. The next EcomExpo is in October, and I plan on being an exhibitor at that one.
People have asked me if it is worth it. Well, I say it is well worth price of admission. If you just take away one small tip (and you will get many tips) it pays for itself quickly.