I think it's about context, really. At a restaurant or hairdresser, you already expect to pay and you already have money out. It's usually not too difficult to slap on an extra few bucks for the waiter. (The tipping model makes much more sense at a restaurant, by the way, where there a lot of people involved in your food prep, not to mention the food cost, vs. a barber where the one person cuts your hair and takes you to check out, and they take turns as broom jockey.)<p>If I want to "tip" Wikipedia, for instance, I have to go find my credit card, type in lots of numbers, possibly setup an account, worry about the individual handling of my card information by Wikimedia, etc. That's way too much effort for drive-by donations a la those at the restaurant.<p>I assume that's what tipjoy and some of these other startups set out to fix. I don't think simplification of and success by tipping is particularly a lost cause, I just think that it wasn't easy or prominent enough. Was there a browser extension? If I only had to enter my info once, and there was a button on my browser where I could send any registered site a tip while I was on the page without any special effort, I think I would be prone to tip more often.<p>By the same token, I think that you're much, much more likely to make some money if you follow the more conventional "x costs x, please pay me" model, even if you surreptitiously proliferate content outside of the paywall to increase exposure.