There are a few problems with this. Venmo, the mobile payment app from New York's and Bit.ly's Andrew Kortina, addresses two of them. First, it's more reliable than memory and not as bulky as a dry erase board. But more importantly, it's alleviating the awkwardness of those you-still-owe-me conversations during the period between the loan and reimbursement, and for recording transactions.

Venmo fans around the city have repeatedly told The Observer how much they love and depend on the app, and it seems to be the social element that's made Venmo sticky. You can't say "fuck you, pay me" to a friend. With Venmo, you send a personal note with each charge and payment, which you can share on Twitter or Facebook. That note might say "fuck you, pay me," but it's okay, because now it's on the internet and it's social media and those things are fun.

"We actually will not let you make a payment without including a personal note," Mr. Kortina said. "We hope that all of the complexity, emotion, and feeling involved in a social gesture start making monetary transactions more personal, more fun, and simply a better experience that feels more like getting a gift or a high five than exchanging money."

Patriot Nate Westheimer added "USA! USA! USA!" to the receipt when he paid Vin Vacanti back for tickets to a U.S.-Argentina soccer game. Podcaster Aaron Crocco tweeted, "Just used @venmo to pay my co-hosts for being awesome on my podcast. I wish EVERYONE used this service. Makes life SO much easier." "Just paid rharwood for January friendship fee," VC Ben Lerer invoiced.

Novelty is also a factor in Venmo's delightability; we hear Jack Dorsey's dongle is also pretty fun.

ajeffries [at] observer.com | @adrjeffries

Venmo opened an invite-only beta in February 2010 and spent that year refining the product, an iPhone and Android app and SMS system that lets people use their phones to make and receive credit and debit card payments. The company has already processed nearly half a million dollars in mobile transactions in January of this year, and its growing volume has brought other perks.

The company just made a big announcement: Because of its growing transaction volume, Venmo was able to considerably cut the time it takes to get money from  users' bank accounts: It now takes between one and three business days instead of four to six business, which should make customers happy as faster transaction times was their most common request.

"We were able to achieve faster withdrawal times mainly because our transaction volume is growing and we're becoming more established as a payments service for friends," cofounder Andrew Kortina said in an email. 

Kortina said that Venmo's crucial innovation was making payments social. "Providing a social payments service is not only about making it easy and non-awkward to settle the bill when you're out to dinner and drinks with your friends; it's also about developing better ways to handle challenges like fraud and chargebacks," Mr. Kortina said. "Part of the reason it takes so long to transfer money using traditional banking systems is because it can be difficult to asses the risk of each transaction. If a sender doesn't have sufficient funds to complete a transaction, and the recipient's account is mistakenly credited, there's real money on the line. Then there's the risk of identity theft and stolen credit cards. We spend a lot of our time figuring out how to prevent fraudulent transactions, and in doing so, we're making use of the rich social data surrounding all of our transactions. This is proving to be a better way to assess risk, and, consequently, banks are willing to work with us to speed up withdrawals. These banks are excited about making legacy systems more efficient and improving the customer experience they deliver on mobile devices."

"The other reason traditional bank transfers are slow is that some banks like to earn money on the "float," and as a result, they hold your money for a few extra days to earn interest on your transfer.  For example, when I use my bank's website (I won't name the bank here) to send money to a friend at a different bank, it takes about 5-7 days to reach my friend's account. That's far too slow and not the model we're after. Our goal is to provide the experience our users want, without manufacturing any delays to earn interest."

The company just rolled out a help center section on its website and hopes to keep making the experience better for users. "Cutting withdrawal times in half is good, but not good enough--we're hoping to make this even faster in the coming months," Mr. Kortina said. "We built Venmo because paying friends back electronically felt clunky, slow, and bland, especially in the age of the real-time, social web.  A payment to a friend--for dinner or a ski trip or anything else--should be as quick and easy to complete on your phone as sending a text message."

ajeffries [at] observer.com | @adrjeffries

The app is free and should be available today, but you need to have accounts with both Foursquare and Venmo to use it.

Gifi should be warmly received at Foursquare, which is counting on third party developers to build applications that will create new uses for location-based check-ins. The more Foursquare-powered apps like this exist, the more chance New York's most promising tech start-up has for becoming a true platform for location rather than just a niche service.