Last week gadget reviewers got their first hands-on look at Microsoft's (Nasdaq: MSFT) much-discussed Kin One and Kin Two phones, which are designed from the ground up to support young hipsters' social media and content sharing habits. So far, the pundits are raving about the phones' novel operating system and the cloud-based "Studio" feature, a flashy private website where all of a Kin user's photos, videos, text messages, voicemails, news feeds, and contacts are collected and displayed. They're mostly panning the hardware itself, as well as the prices on the Verizon data plans needed to make the phones useful.

But whether or not the Kin phones have what it takes to win over today's teenage and twenty-something Facebook/Twitter/MySpace addicts, it seems likely that they'll reignite interest in the idea of "lifelogging" -- the attempt to create a comprehensive digital record of one's daily experiences. Up to now, lifelogging enthusiasts have been forced to handle most of their data-capture and archiving tasks consciously and deliberately: if you came across a Web page you might want to consult later, you could manually bookmark it or save it to a service like Evernote or iCyte; if you wanted to share or store a photo you snapped, you could put it on Flickr or Photobucket or Tweetphoto.

The Kin phones' big redeeming feature, according to the reviewers, is that this sort of stuff all happens behind the scenes, automatically. Within five minutes of snapping a photo on a Kin phone, for example, the picture is wirelessly transmitted to Microsoft's servers and added to your Studio, where it stays forever, adding to a running timeline of your life. "The implications here are huge: This is how cloud stuff is supposed to work," writes Gizmodo's John Herrman.

The Kin phones offer a taste of what may be coming sooner than anyone expected: a world full of cheap, portable sensing devices that document every interaction, every experience, and every perception we have, continuously uploading the information to vast server farms in the sky where the cost of storage is only a tad above zero. As it happens, this is exactly the world portrayed in Total Recall: How the E-Memory Revolution Will Change Everything, a 2009 book by Microsoft researchers Gordon Bell and Jim Gemmell. But even Bell -- who began perhaps the world's most ambitious lifelogging project back in 1998 -- might be surprised by how quickly his vision is growing into reality.

Soon, Bell and Gemmell wrote last year, everyone will be able to keep a digital diary recording everything about their lives that's recordable:

If you choose, everything you see can be automatically photographed and spirited away into your personal image library with your e-memory. Everything you hear can be saved as digital audio files. Software can allow you to scan your pictures for writing and your audio files for words to come up with searchable text transcripts of your life. If you choose, you can save every e-mail you send and receive and every Web page you visit. You can record your location and path through the world. You can record every rise and dip in your heart rate, body temperature, bloodsugar, anxiety, arousal, and alertness, and log them into your personal health file.

All that will be needed to achieve this vision of "total recall," Bell and Gemmell wrote, is an array of cheap, wearable hardware -- "unobtrusive cameras, microphones, location trackers and other sensing devices that can be worn in shirt buttons, pendants, tie clips, lapel pins, brooches, watchbands, bracelet beads, hat brims, eyeglass frames, and earrings" or even implanted inside the body. Bell, who helped design Digital Equipment Corporation's giant PDP and VAX computers in the 1960s and 1970s, is himself a walking laboratory for the lifelogging technologies -- as part of his ongoing My Life Bits project, he wears a prototype "SenseCam" that snaps a digital photo every few minutes.

But there's one place for such recording hardware that Bell and his co-author didn't include in their list: the pocket, purse, or holster where you keep your mobile phone. Judging from developments like Kin Studio, ordinary cell phones, not lapel-pin spycams, will be the wedge devices that provide millions of people with their first experience of lifelogging.

While the Kin system is currently the coolest example of automatic cloud-based sharing and storage, it's far from the only one. Nokia (NYSE: NOK) introduced a mobile-fueled multimedia diary tool called Lifeblog way back in 2004, for example (it's since been supplanted by a more prosaic "Nokia Photos" service), and Apple's MobileMe subscription service provides automatic wireless synchronization of appointments and contact lists across multiple Apple devices (iPhones, iPads, MacBooks) as well as cloud-based storage for photos and other data.

But how many people really need or want to be lifeloggers? Apart from the obvious privacy and security issues that arise in a world where Facebook and Google and Microsoft store so much of our personal data, how much of information that we're stockpiling does anyone else care about -- and how much of it will we really need it later?

There's a fascinating article in the May issue of Communications of the ACM (that's the Association for Computing Machinery, for all you non-geeks) that pretty much tears apart Bell's lifelogging concept, accusing him and other proponents of the "e-memory revolution" of charging ahead on the technology of digital archiving without stopping to ask what practical purpose a comprehensive lifelog might serve. More than that, the authors believe that lifelogging researchers naively confuse "e-memories" with real human memories, and ignore decades of psychology research on how organic memories are generated and retrieved.

What makes the article doubly interesting is that one of the co-authors, Abigail Sellen, is Bell's colleague at Microsoft Research. (Though she's part of the Cambridge, UK, branch, while Bell is in San Francisco.)

Sellen and co-author Steve Whittaker, of IBM's Almaden Research Center in San Jose, CA, acknowledge that lifelogging systems might have any number of uses. They divide these up into "the five Rs," or recollecting (help reliving specific life experiences for pratical purposes such as locating a lost object), reminiscing (accessing the emotional or sentimental content of a historical experience), retrieving (finding specific documents or records), reflecting (examining patterns in experience and reframing the past), and remembering intentions (simply put, keeping a to-do list of prospective events).

All of these are important forms of recall. Unfortunately, according to Sellen and Whittaker, there is little evidence that lifelogging systems help with any of them. Bell writes in Total Recall that he felt compelled to hoard and eventually digitize huge stacks of old paper files "because I knew that someday, for some reason, I would need to refind at least one old item." In Bell's world, only a "total capture" approach can prevent the loss of potentially needful data. But Sellen and Whittaker cite studies showing that even the digital files people go out of their way to save, such as photos and videos or scanned documents, are rarely accessed later. "Archival data may be less valuable than the considerable effort expended on these systems would justify," they write.

Going further, the researchers argue that to the extent that lifelogging is intended as a backup system for our faulty and limited human memories, it's misconceived. A fancy Kin-style multimedia timeline of moments captured through various technological lenses, after all, is a far cry from a life's collection of authentic autobiographical memories. And when it comes to triggering memories, a place, face, or name is usually much more effective than a date on a timeline.

"Despite the memory terminology used in lifelogging work, little attention seems to focus on human memory and how it operates," Sellen and Whittaker conclude. If lifelogging proponents really want to build something useful, their article argues, they should focus on the real shortcomings in human memory. (Remembering intentions, for example, is much harder for most people than recollecting experiences.)

The overall implication of Sellen and Whittaker's piece is that lifelogging is a technology solution -- ubiquitous sensing meets wireless communications meets cheap cloud-based storage, in this case -- in search of a real problem. All those tweets and text messages and status updates and digital snapshots, in other words, may have a shelf life about as long as the time it takes for the items to scroll off the tiny screen of a mobile phone.

It's remarkable to see such a debate playing out between two researchers at the same company -- but it's even more ironic that the company is Microsoft, which built both the Windows Phone operating system running on the Kin One and Kin Two and the Kin Studio platform.

My personal prediction is that certain limited forms of lifelogging will become more and more common, but that few people will choose to go the total-capture route that interests Bell. Photography, for example, is one realm where putting everything online automatically seems useful and natural, especially if you have a "cloud phone" like the Kin or your digital camera has an Eye-Fi memory card (a nifty labor-saver that sends your photos up to your favorite photo sharing site as soon as you come within range of a Wi-Fi network).

I'm also a fan of online notekeeping systems like Evernote, iCyte, and Springpad, which let you store, organize, and annotate copies of Web articles, voice memos, images, scans, or other discrete digital items you might want to refer to later. And just out of paranoia, I back up the hard drives on my work and home computers on two separate cloud storage systems, Carbonite and Mozy. I'm sure all of these things will become even easier and more automatic. But I don't feel a burning need for a system that would capture my every word or thought, because most of them, to be frank, just aren't that earthshaking.

I've confessed in previous columns to being a digital pack rat. But one nest can only hold so much, and even an "external brain," as Evernote's creators have labeled their service, can get cluttered. And in the end, perhaps all this documenting, collecting, and reviewing is more obsessive than constructive. Every minute we spend ruminating on the past is a minute stolen from the present -- which is the only time, after all, when anything ever really happens.

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For a full list of my columns, check out the World Wide Wade Archive. You can also subscribe to the column via RSS or e-mail, and you can download Pixel Nation, an e-book version of the first 80 columns, as a free PDF file or a $4.99 Kindle edition. Wade Roush is Xconomy's chief correspondent. You can e-mail him at [email protected] or follow him on Twitter at twitter.com/wroush.

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