Sometimes, in the face of rampant metaphors, strained similes, and overextended analogies, we wordsmiths have to stand up and say “Enough is enough!”

One trope that deserves to be trashed, right now, is the rash of analogies between TiVo and practically anything else involving time-shifting or digital content. Podcasting, many people have repeated, is like “TiVo for radio.” (I’m guilty of this one myself, so this blog entry is partly an act of penance.) Comictastic, a program for collecting and reading comics in a Web browser, has been called “TiVo for comics.” The San Jose Mercury News, of all publications, recently called hardware-simulation software made by Virtutech “like TiVo for software engineering.” Pluck, which is, as far as I can tell, little more than a standard RSS feed aggregator, has been called “TiVo for the Web.” And just this week, the New York Times published a column referring to RSS itself as “TiVo for the Internet.” All of these analogies are flawed, but the last one is so egregiously wrong, for reasons I’ll get to in a moment, that it tipped me over the edge. I can no longer stay silent.

TiVo, of course, was one of the first companies to make mass-market digital video recorders, or DVRs (also known as personal video recorders, or PVRs). The idea behind the DVR is identical to the idea behind the VCR: you program the device to record a live program as it is broadcast, and then you watch it at your convenience – a practice called time-shifting. There are only three real differences between DVRs and VCRs. First, DVRs have hard drives, which means they can store more hours of programming than old VHS tapes. Second, most DVRs come with an electronic programming guide that makes choosing the programs you want to record slightly easier than programming a VCR. Third, DVR recordings are digital, which means they are easy to copy, share, or watch on your computer, if you know how to hack into your device.

Somewhat confusingly, the actual TiVo hardware – what the company calls the “TiVo box” – has also come to be known simply as TiVo. And while there are other brands of DVRs, such as ReplayTV, TiVo has emerged as the generic term for DVR technology. Just as every facial tissue is a Kleenex and every photocopy is a Xerox, every DVR is a TiVo.

When people say some new technology is “like TiVo for [insert medium here]”, it’s rarely clear which aspect of TiVo they are thinking of. Is it time-shifting? Hard-drive storage? An easy-to-use program finder? Often, it’s none of the above.

Let’s start with podcasting – a case of mass amateurization in which people record their own audio shows and distribute them on the Web via RSS feeds. Here, I can do no better than quote a wonderful blog entry at Podcastingnews.com by Elle Webb:

Over and over, when writers try to describe what podcasting is, they use the same worn-out metaphor: Podcasting is like Tivo for Radio.

On first read, the comparison doesn’t seem so bad. Both Tivo and podcasting do let you watch or listen to programming on-demand. They are both cool. They both let you avoid commercials.

What’s different about them? Just about everything else!

• Tivo is a product that you buy. Podcasting is a standard that you use.
• Tivo lets you record or stop live TV. Podcasting doesn’t do anything with live radio.
• Tivo is controlled by one company. Podcasting isn’t controlled by anyone.
• Tivo lets you time-shift TV. Podcasting lets you download things automatically from the Internet.
• There’s little or no competition in the world of Tivo. Hundreds of developers are competing to develop the podcasting platform.
• Tivo discourages content creation, while podcasting encourages it. Tivo diminishes the impact of advertising within broadcast content, reducing the incentive to create new content. Podcasting removes barriers to content creation and distribution, which has resulted in an explosion of new content.

Comparing podcasting to Tivo is bit like dancing about architecture.

Podcasting is not like Tivo for radio. Podcasting is using newsfeeds to distribute information about audio files. It’s a way that you can use your computer to automatically download an amazing variety of shows, so you can listen to them (or watch them) at your convenience. It’s not controlled by any company, so any one with a computer and an Internet connection can make a podcast.

Tivo is a little like podcasting…..except that Tivo locks you into one vendor, Tivo only lets you watch the same junk that you already watch, Tivo’s adoption rate is pretty slow, you have to buy Tivo, and Tivo does nothing for content producers.

When you witness how thoroughly Elle demolishes the podcasting-TiVo comparison, you start to see the flaws in the other TiVo analogies as well. Virtutech, for example, makes software that can be used to simulate the way other software will run on various hardware platforms. One of the key selling points of Virtutech’s simulation system is that it allows programmers who are trying to debug a piece of software to “stop” a program as it is running, at the exact place in the code where a problem occurs, to see what’s happening under the hood. (This wasn’t possible in the past, when programmers had to let a program run all the way through, look at the often-buggy results, and then go back and try to reconstruct the problems in the code that led to the bugs.) A feature of Virtutech’s system called “Hindsight” even lets developers run a program in reverse. But in what sense is this “like TiVo for software engineering”? The only apparent similarity is that TiVo also has pause, fast-forward, and rewind capability. But VCRs had those features too, so why fasten on TiVo?

Now to RSS. RSS feeds are small, easily-shared XML files that contain summaries and addresses for Web content such as news articles. An RSS feed aggregator is a program that “subscribes” to the RSS feeds of your choice and presents them in a single browser window. RSS is going to be one of the key technologies changing the way we use PCs and the Internet over the next decade, so it’s important that we help people get the concept straight now, before too much misinformation has spread.

Comparing RSS or RSS aggregators to TiVo is not only unilluminating, it’s downright misleading. Louise Story, the author of the New York Times column, writes that RSS is “somewhat like TiVo for the Internet” because “by letting people have content pulled from Web sites and fed to their own computers automatically, they can then store it for later viewing.” Story is referring to the same on-demand aspect of TiVo that Elle Webb mentioned. But there’s a big hole in this logic. On the Web, all content is viewed on-demand. RSS feeds aren’t like video recordings; they don’t represent information that’s here now and gone the next instant, like a broadcast. Collecting RSS feeds into an aggregator simply gives Web users a quick overview of sources they would otherwise be forced to locate one at a time.

There is one class of computer technologies that’s legitimately analogous to TiVo. It’s the growing collection of hardware add-ons and software packages that allow people to record live radio (whether it’s streaming over the Internet or broadcast over the air) and listen to it later on their computers. The Radio Shark records live AM or FM shows for later playback on a computer, and even pauses radio, just like a TiVo or a ReplayTV can pause TV. Timetrax makes a little box that allows XM Radio subscribers to time-shift their listening. ReplayRadio from Applian Technologies can tune into any Internet radio channel and record shows at a pre-programmed time. These products are, quite literally, like TiVo for radio.

But that’s the exception proving the rule. Maybe the real reason people abuse the TiVo analogy is the paucity of terms in the English language for the manipulation of time. “Time-shifting” is itself an awkward phrase, as if we were literally transplanting 8:00 pm Tuesday to 11:00 pm Wednesday. And fast-forwarding, pausing, and rewinding–concepts rooted the era of film and videotape recording–are virtually our only ways of thinking about navigating audio or video content.

Or the problem could simply be TiVo’s high “cool factor.” At this moment in our culture, any reference to TiVo – no matter how nonsensical – confers some street cred on the speaker.

I have an idea. Before we start seeing every recording gadget as a TiVo, every group as wise, every back inventory as a Long Tail, and everything bad as good, let’s take a breath and see if we can invent a few new analogies that make things clearer, not murkier.