Despite all our best efforts, most of us are still drowning in e-mail, and much of it is sent by machines rather than real people. OtherInbox, a Web service launched this weekend at the South by Southwest Interactive (SXSW) conference, in Austin, TX, promises to rescue e-mail-swamped users from this problem.

The messages that the new service handles usually aren’t spam. Instead, they’re legitimate communications from trusted companies that sometimes contain useful information: alerts, special offers, and service updates. But the steady influx of these automated messages is a familiar problem for most users.

The basic idea, explains OtherInbox CEO Josh Baer, is to categorize e-mails based on their source. For example, all e-mails from Amazon are automatically placed in one folder, and all e-mails from Facebook go into another. Baer says that he built the service after realizing that automated e-mails make up a huge percentage of all the messages that many users have to deal with–often as much as 50 percent.

Users can get an e-mail address through the service itself or can connect OtherInbox to an existing Gmail account. When a user gives the service his login credentials for Gmail, it sorts through his inbox, analyzing its contents. The service then removes automated messages, leaving a cleaner inbox containing messages from real contacts only. Before diverting these messages, however, the service shows the user its planned reorganization, giving him the opportunity to accept or override any changes. It also shows him what percentage of his e-mail, on average, is automated, and estimates how much e-mail he could get rid of using the service.

Automated e-mails are then archived in Gmail and copied to OtherInbox, where they’re organized in folders. The user also receives one daily e-mail summarizing all the automated messages that have come in and what OtherInbox has done with them. OtherInbox also lets users deal with automated e-mails in batches–for example, allowing them to block one type of e-mail with a click if it turns out that it simply isn’t useful.

Baer explains that the concept stemmed from his personal e-mail habits. Since he owned his own domain name, he used to give different e-mail addresses to different websites. This meant that he could quickly identify the source of an e-mail and block messages sent to those addresses if necessary. Although Baer decided that this approach was too complicated to be convenient for most users, OtherInbox still lets users give out multiple disposable e-mails if they choose, in addition to offering its automated analysis.

“OtherInbox is a rare startup that solves a very real, very urgent need of anyone who uses email.” says Carla Thompson, a senior analyst for Guidewire Group, a firm that analyzes early-stage technology companies. She adds that she is impressed with how easy it is to set up the service, although the user interface could be adjusted to work faster and more smoothly. “I’m willing to wait for those improvements because it’s my favorite kind of technology: it solves a real need without much thought or effort from me,” she says.

Over the past few years, numerous services have sprung up to help users deal with e-mail overload. For example, a plug-in for Microsoft Outlook called Xobni enhances the software’s search features and shows additional information about all the interactions between a user and her e-mail contacts. Another service, called NutshellMail, collects and organizes messages from different e-mail and social-networking accounts in one place. Baer says that what distinguishes his service is its attention to automated e-mails, which users probably want to receive but don’t want to read every time they open their inbox.

Nova Spivack, CEO and founder of the Semantic Web company Radar Networks and a judge on an awards panel at SXSW, says that OtherInbox could certainly be useful for reducing e-mail clutter. However, Spivack wonders whether users will find that the e-mail is out of sight and out of mind, and hence will simply stop reading automated messages. He adds that the service might be more practical if it were contained within an existing e-mail account instead of in another inbox.

While the first step is to get automated e-mails organized and out of the user’s inbox, Baer says that machine-learning algorithms allow OtherInbox to do smarter things, such as recognize upcoming events and automatically creating calendar entries for them. In the future, he says, the service will also recognize and file receipts received from online retailers. “From a machine-learning perspective, the automated e-mail is the good stuff,” Baer says.

The basic service offered by OtherInbox is free, but the company plans to make money by also offering a premium option. Among other things, the premium service will let users store e-mails for longer periods. The company may also use the information that it collects to provide marketers with aggregate data on customer behavior–for example, which marketing e-mails are most often read by users. However, Baer stresses that the company does not intend to share information about individual users. He adds that OtherInbox will offer integration with Yahoo Mail, Hotmail, and Outlook later this year.