Sparrow, the creators of the popular OS X and iOS e-mail client of the same name, has been acquired by Google, according to a posting on the company's website this morning. Sparrow's developers will now be joining the Gmail group, where they will be working toward an unspecified "bigger vision."

The most immediate fallout from the acquisition is that the Sparrow mail clients will no longer see feature updates—this was implied by Sparrow's announcement and confirmed by both a Google spokesperson and a second announcement that went out to Sparrow users who had signed up for the product's mailing list. According to the message, the OS X and iOS mail clients would continue to be supported and critical bugs and security issues would be patched, but the team does not intend to release any new features for either app. The desktop client has been around since late 2010 and is fairly mature, but the iOS version has only been around for a few months and the acquisition makes features like support for push e-mail extremely unlikely.

What happens now?

Neither Google nor Sparrow CEO Dom Leca could comment on what exactly the Sparrow team would be doing within the Gmail team, but given Sparrow's area of expertise, one possibility is that the team will be working on some sort of desktop e-mail client for Google's mail service.

While we wouldn't rule this option out, it would seem to be an odd choice given Google's past. On the desktop, the company has long advocated that everything should be done within the browser, which has led to everything from a browser-based app store to a plugin that allows the browser to run x86 binaries to an entire operating system that puts everything, including the file explorer, into the Web browser. To release a desktop Gmail client after years of getting by without one would be an abrupt about-face on this strategy, particularly because Gmail remains one of Google's biggest products.

What's more likely is that the Sparrow team's expertise will be put to work improving Google's mail client for iOS. The Gmail client for iOS as it stands is not actually a mail client at all, but rather a wrapper for Gmail's mobile site—it's considerably less smooth and streamlined than either the iOS Mail app or the existing Sparrow iOS client. It wouldn't be surprising at all if the Sparrow client as it stands reappeared, in re-branded form, as the official Gmail iOS client in the coming months.

Finally, there's the Android possibility: while Sparrow was never ported to Android, the company's work on a touch-enabled e-mail client for iOS could be applied to produce a new e-mail client for Android phones and tablets. Android's Gmail app itself is fairly robust, but the IMAP mail client used in stock Android leaves a lot to be desired (especially if you're using a pre-Ice Cream Sandwich version of Android). Many of the features in Sparrow for iOS, including standards like conversation view and bare necessities like the ability to create folders, would go a long way toward ameliorating problems with the current client. Sparrow's mail clients have always offered robust support for Gmail, so it's even possible that the Gmail and IMAP clients could finally be unified into one client.

Even without knowledge of Google's plans for Sparrow, it's clear that current Sparrow customers are being burned, particularly those who have paid for the iOS and OS X clients. To expect software support in perpetuity is one thing; to charge your customers $2.99 for an iOS app and then end-of-life it just four months later is another.