Even PayPal, alternately an object of scorn and fear by banks in its early days, has gotten into the bank partnership game and is working with a couple of hundred of them, including USAA, to offer a similar service. With its offering, recipients end up with money in a PayPal account, and they can transfer it to their checking account if they so choose. “We definitely believe that people are going to do this from where they are most comfortable and that is likely going to be where they have their direct-deposit relationship,” said Dan Schatt, general manager of financial innovations at PayPal.

The big banks don’t fear PayPal today as much as they do iTunes, Google or Facebook. Given the huge numbers of younger users of those services, it is possible that one of them may try to build a platform for easy person-to-person payments. That may be the biggest reason clearXchange, the joint venture by Bank of America, Chase and Wells Fargo, emerged.

Those three companies claim to have about half of all online and mobile banking customers, so they can certainly throw their weight around. The clearXchange offering hasn’t amounted to much so far, however, given that users in the test markets can’t even send money to any banks outside the joint venture yet, something that ING Direct customers have been able to do for more than five years. (In fairness, customers of those three banks do have other bank-offered services for moving money to friends and family, including Chase’s QuickPay service, which it advertised during the Super Bowl.)

All of these interoperability issues aside, though, the person-to-person payment services still have ease-of-use challenges. Recipients may not know their bank account information offhand when they’re out for dinner or at work, or they may be wary of entering their bank information into an unfamiliar site.

Also, people who don’t already have a PayPal account may be annoyed if they’re told to sign up for one to collect on a birthday present or the money a friend owes them, or they may just prefer a check rather than deal with remembering to log on to PayPal to move the money over to their checking account.

“The consumer still has to think about it,” said Mr. Higdon, the former Citi banker. “They should get a text message and should just have to say yes or no, and then the money is there. Until we reach that point, we’re not going to see widespread consumer adoption.”

One thing that might get consumers on board faster is if the money moved instantly from one bank account to another at a different bank. But because these payments move along the same electronic railroad tracks that checks do, it can still take a couple of days. That is profoundly irritating to people who think they’re handing money across the table with a cellphone only to find that the money is actually caught up in a decades-old intrabank system that desperately needs updating.