As you may already know, Square Inc., the new mobile card reader and payment service, is becoming more popular with merchants. In fact, they have increased their payment volume by 25% since March. Currently they are processing payments at an annualized rate of $5 billion. But, how have they become so popular so fast?

That’s easy, it’s all about money. If your a merchant and you make a sale before 5pm, Square will make that money available to you the next business day. If you take the conventional credit card route, you may be waiting as many as five days for the conversion from credit to cash to reach your accounts.

Currently Square’s card readers are available for use with Apple products including iPad and iPhone, and also with Android devices. With 25% volume growth they must be doing something right at Square, but why haven’t we has a breakthrough like this in payment methods before?

Square’s CEO Jack Dorsey comments:

“My background is in real-time transactions,”

“I love low-level stuff. Twitter is about minimizing frictions around communications. But there have been innovations in communications for hundreds of years, and lots of them had really good design. But you can’t say the same thing for payments. When I think of the opportunity to design that, to get down to its essence—I don’t think anyone has ever done that before.”

“There’s no greater indicator of interest than purchasing something,”

I guess it’s true there is no better indicator for what people’s interests are than how they spend their money. But, what does Square plan to do with that information? No mention of that yet, but Square is progressing quickly since their introduction in 2009 and a lot of that has to do with the value they bring to retailers.

Last week we reported that Dorsey might be out soliciting funds for another mega funding round, but we have yet to have those rumors substantiated. What we do know for sure is that Jack has been hiring some seasoned talent the past couple months in an effort to double Square’s current staff of about 250 to almost 500. Notable hires include Ricardo Reyes from YouTube and Tesla Motors, Alyssa Cutright from PayPay, and Jesse Dorogusker from Apple.