If there's one thing the digital revolution has taught us, it's that we shouldn't get too attached to anything. Technology has a way of seizing long-held ideas and entrenched industries and turning them upside-down.

Disruption is rarely the result of a single gadget or innovation, however. It's typically when two or more technologies converge that the real changes start to happen.

For this look at the most disruptive high-tech events of the last quarter century, we divided developments into pairs that have formed an effective one-two punch. On the following pages are our picks for the ten technology duos with the biggest impact.

10. DVRs + Entertainment on Demand

Remember programming your VCR to record TV shows? Of course you don't, because nobody did it--the task was too difficult and time-consuming.

Fast-forward to the late 1990s and the introduction of the TiVo and ReplayTV digital video recorders. Time-shifting programs and fast-forwarding through commercials became as easy as pressing a couple of buttons. Suddenly people were no longer shackled to the arbitrary schedules of TV programmers and the obnoxious pandering of advertisers. Cable and satellite providers rushed out their own DVRs, and millions of folks began "TiVo-ing"--even those who had never touched an actual TiVo.

Like the best disruptive tech, DVRs returned control to users--and made consumers hungry for even more control over what they watched, when, and where. In 2005 the Slingbox introduced place-shifting, making it possible to watch your TV (or your TiVo's content) over any broadband connection. Later that year the video-enabled iPod sealed the deal, and broadcast content was permanently untethered from the tube.

Though iTunes' video library was far from comprehensive, it proved that if people get an easy alternative to file sharing, they will pay for what they want. Today, video-on-demand services--including ad-supported ones like Hulu.com that are owned and operated by the broadcasters themselves--are booming. Thanks to TiVo, iTunes, and other similar advances, we now expect our entertainment to be delivered to us wherever we are, whenever we want it, on any device that's handy.

Disruption: The whatever/wherever/whenever model of media consumption is turning both Hollywood and the consumer electronics industry on their heads, and forcing advertisers to rethink ways to capture our attention.