Here is a thought provoking post from Brian Smith about agents, adware and toolbars on ComparisonEngines.com. I like that he presents the core value of 'adware' and phrases it in a more general context of 'agents'.
Long ago I had been very excited about agents and event driven applications but spent most of the recent past working just on messaging systems (subscriptions, notifications, etc) rather than the agents themselves. Maybe it's time to go back and revisit agents. Recently I've had this notion that an interesting paradigm for empowering people to build agents might be to use a spreadsheet with event inputs and message outputs - but I haven't even started down the road of working out what it would look like. I think general folks wouldn't understand specialized agent building languages but might be able to poke things together with a visual tool.