But, like the brain, technology is a constantly evolving, open system, subject to environmental influences. On a small scale, think about how files must be filtered to change formats. With compression, images and videos lose resolution and quality. But programs can alter photos in ways that enhance them, too. The computer is reassembling and reprocessing the files in each of these cases.

And, your computer may eventually break down, purging your files (which is why hard-drive backups are recommended).

Social media also gives new meaning to digital storage. Where you share a photo, how it gets tagged and what its caption says all create a memory around the image that wouldn't exist otherwise, Tranquillo said.

And your digital memory becomes influenced in even stranger ways now that there are social networking tools that update content without your direct intervention -- for instance, posting on Facebook or Twitter when you arrive at a location. With Facebook's Timeline feature, other people can contribute to your online life history by posting photos, videos and comments.

"This is the crowdsourced self," Tranquillo said. "As the viewer changes, so does the collective construction of 'you.'"

Aiding the aging brain

You may have, at one point or another, struggled with multitasking. That's because when you move from one task to another, your brain shuts down one neural circuit in order to move on to the next. That's inefficient, and studies have shown that it's harder for older adults to re-establish that initial circuit and return to the first activity.

But if you use the Internet in ways that make your life more efficient, it could theoretically reduce the multitasking that you do. You don't have to fumble through an address book frantically, or find your way out of an unfamiliar neighborhood unguided, while thinking about other things.

That's important as the number of Americans with Alzheimer's disease -- currently 5.5 million -- continues to climb. As people get older and their memory begins to decline, they are still able to access information through search, helping to compensate for their own memory deficits.

Small is working with computer scientists at UCLA on games that can help older people improve their ability to remember names and faces. Plenty of research is in the works to find brain-boosting pharmaceuticals, supplements and foods (most recently, berries), although nothing is a certain supplement.

The dark side

The downside of technology is that it can make us less thoughtful and less creative. And we may spend less time communicating face to face, which can reduce the quality of relationships. A 2012 survey of American girls found that spending time multitasking with various digital devices, watching video or communicating online is associated with abnormal social tendencies.

It's also not certain that freeing our memory from addresses and phone numbers frees up room to be more creative, Tranquillo said.

What's more, a lot of creative thinking depends on having ideas accessible in a way that preserves their context, so merely writing them down to keep externally -- whether on a computer or a notebook -- doesn't necessarily allow you to do novel things with them.

Tapping storage potential

It's not hard to appreciate how, in terms of sheer volume, computer memory has outpaced humans. Google's Gmail offers 10 gigabytes of storage. Tom Landauer, professor of psychology at the University of Colorado at Boulder, estimated in 1986 that the human brain holds 200 megabytes of information.

And what if we stored all of an individual's experience? Landauer calculated that if a person only takes in one byte per second, and lives about 25,000 days, that's still only 2 gigabytes.

But that's just a tiny fraction of estimates for the brain's total storage capacity, which is as high as 2.5 petabytes (2.6 million gigabytes), based on the number of neurons (1 billion) and connections to other neurons.

That sounds like a lot, but McKinsey Global Institute estimated that consumers stored 7 exabytes (7.5 billion gigabytes) of new data on PCs, laptops and other devices in 2010.

Obviously, there is too much information out there to hope to compete with our minds against machines. But there are certain things you can do to help your brain live a long, healthy life so that you are using it to its fullest potential.

Engaging in activities that are new, difficult and complex forces your brain to lay down new cellular connections, Nussbaum said. Exercise and healthy diet are also important to brain health. Emerging research in meditation and spirituality has indicated that mindfulness -- practices associated with being in the present moment -- help, too.

"We tend to really get so impressed with the latest gadget, the latest phone, the latest whatever it is," Nussbaum said, "and we forget that all of the technology that built it came from the human brain."

What is there left to remember that's not out there on the Internet? You'd better know your most valuable digital secrets by heart: Your passwords!

Share your thoughts about how digital technology helps or hurts your memory in the comments.