The smartphone has emerged as the true "all-in-one" device.  Stop for a minute and think about the sheer number of stand-alone devices and services the (not so) humble smartphone has killed off or shrunk down over the past decade.  I started tallying up the obvious ones and the list grows quickly.

Corded phones and landline services have been a big victim to the cellular world, but I always feel like there's a bit of overhype when it comes to the smartphone replacing all wired services.  Back in the '90s, prior to the proliferation of DSL and cable modem services, many households purchased two and three analog phone lines for the sole purpose of connecting on the Internet and other online services via modem.  As broadband rolled out, people started rolling back analog lines since they got plugged into faster dedicated speeds and modems died.

Still, the smartphone is now the go-to device for teenagers to communicate with the parents and each other; no more having to "share" an analog phone line with mom and dad.  

The jury is still out on now far and fast smartphones can displace desktop handsets in the business environment.  For security, safety, and simple coverage issues, corded phones can assure quality of service in many places where you just don't get a good cellular signal – despite all the promotional hype.  T-Mobile's announcement of a LTE "mini tower" – also known as a femtocell or small cell – is the most recent run by a cellular company to leverage existing broadband coverage to extend where service can be delivered.   

But there's no doubt that smartphones are making a significant impact upon businesses, judging by the surge in BYOD (Bring Your Own Device) policies and continued noise about "cord cutting" by eliminating desktop phones in certain small business situations.

Categories where smartphones have clearly killed or shrunk the market include PDAs, GPS devices, MP3 players and digital cameras.  The Personal Digital Assistant (PDA) was short-lived because its functions were limited and it had to be synced with a larger computer – remember, this was a pre-cloud device.  GPS devices have been attacked from two directions, between automobile companies plugging in GPS as a native "app" within most new model cars and the smartphone providing turn-by-turn directions via Google Maps or similar app.  Advantages the smartphone offers over stand-alone  devices are near-instant map updates, rather than having to download updated apps at some subscription or expensive price (Go price VW CD/DVD map updates), the ability to provide real-time traffic condition information, and even warnings of potential speed-traps.

MP3 players can still be had, but most people now prefer to keep, store, and play music via smartphone app.  The current generation of babies will innocently ask "What's an iPod?" in a few years, since mom, dad, and grandparents play music (and videos) directly from the phone.   Cloud and streaming services, after a rough start, are also in full swing as options to static-play MP3 libraries and devices.

Good quality smartphone cameras have made digital cameras a rare breed.  For quick reference snapshots and social media, the smartphone is a much better option than lugging around a dedicated camera and having to fret with batteries.  Digital cameras and dedicated camcorders for video have their uses, especially when providing better zoom and optics for capturing events and providing dedicated battery power to taking images, rather than drawing down smartphone run time.

Keeping track of time and appointments has been impacted by smartphones.  A number of people I know have stopped wearing watches, using the clock on the phone to keep track of time.  My bedroom alarm clock has been unplugged. I can save energy and get a friendlier wake-up tune by simply using the alarm function on my phone.

Computers will be the next area where smartphones challenge the status quo.  Already you can run many apps from a phone just as easily as from a tablet or laptop/desktop, but with the constraints of size and user interface (touchscreen).    Microsoft plans to have a core set of Windows 10 applications be "universal" in function, sharing the same data and able to run equally well from smartphone to tablet to PC, with the apps self-configuring based upon the screen size and other resources available. People will be able to start editing a document on one device and switch to another device without headache.

But the phones of the future will hold enough computing power to support many tasks currently conducted on a PC.  Doing work will be a matter of dropping your smartphone into a docking station to provide power and links into a full sized screen, keyboard, mouse, supplemental storage, and faster wired bandwidth. You can sort-of do this today with Microsoft phones, but I expect a better, more "real" PC experience to be available from a smartphone in about three to five years.