This is a very good question, and I don't have any answers.

But one anecdote that might be relevant...

My wife and I were on a date last month at Chima, a Brazilian Churrascaria. The waiter took our drink orders on an iPhone. Throughout the rest of the night, we could ask any of the wait staff for something, they would just punch it into their iPhone and someone else would bring it right out. The system worked flawlessly. (This was also our first date in 10+ months, so I was probably pre-wired to be happy/impressed with anything.)

At the end of the meal, I asked to play with the app. It was really well done, with large, intuitive buttons, and a simple interface: [1] enter the table number, [2] choose the item category, [3] choose the item.

Most surprising of all: it was actually his iPhone. The servers get the choice of using one of the house's iPod Touches, or their own iPhones.

Now, Chima is an upscale, national chain, so it could be years (or never) before this trickles down to your local neighborhood bar, but I thought this was an inspiring indicator of how mobile technology might be integrated into the service sector.

Do you remember the name of the app? I'm curious to know if it is something brsnded or white-label.

I'd think the penetration of non-cash tipping would be low until some sort of casual payment system got as easy as Bump and cheap enough in requirements (including the phone) that people in those service jobs could use them.

Mind, smart-phone capabilities will trickle down to cheap, no-contract phones eventually. Some smart developers and companies will be ready for that.

The future of tipping is 25%.

It used to be 15%, now it's often 20%. As current economic trends continue, expect it to go up. As for payment method, cash is best, and will continue to be preferred.

Really? i'm still at 10%, 15% if service was good. $2 tops if it was empty and i had to wait.

I've lived in the UK, Italy, Uganda, and Cambodia, in addition to the US.

All of them have tipping.

Really? around the same 'price' in the US?

places i've lived it was an optional 10% if service was good. usually no tip above $1-2 euro for everyday stuff

The American 15-20% is less common, but I think 5-10% is becoming increasingly common in Europe. It partly depends on whether the restaurant explicitly lists a "service charge" on the bill; if they do, no tip is expected, but if they don't, in many countries it's customary to leave 5-10%. At least, that seems to be the case in Italy, Germany, and the UK. Nobody in Denmark really tips, except perhaps by rounding up. Sweden seems to tip around 5%? But Swedes I know seem to disagree on the question.