Tablets will not replace PCs -- at least not as you think they might

Tablets have seen quite a bit of popularity, and some people now ask: When will tablets replace PCs?

To which I answer: They won't, at least not in the way most folks think of replacing PCs.

The issue of replacement is subtle.

To examine the subtleties, let's review a previous revolution that saw one form of technology replaced by another.

Did PCs replace mainframes? In one sense, they have, yet in another they have not. PCs are the most common form of computing, used in businesses, schools, and homes. Yet mainframes remain, processing millions of transactions each day.

When microcomputers were first introduced, one could argue that PCs had replaced mainframes as the dominant form of computing. Even before the IBM PC, in the days of the Apple II and the Radio Shack TRS-80, there were more microcomputers than mainframes. (I don't have numbers, but I am confident that several tens of thousands of microcomputers were sold. I'm also confident that there were fewer than several tens of thousands of mainframes at the time.)

But sheer numbers is not an accurate measure. For one thing, a mainframe serves multiple users and a PC serves one. So maybe PCs replaced mainframes when the number of PC users exceeded the number of mainframe users.

The measure of users is not particularly clear, either. Many users of microcomputers were hobbyists, not serious day-in-day-out users. And certainly mainframes processed more business transactions than the pre-internet PCs.

Maybe we should measure not the number of devices or the number of users, but instead the conversations about the devices. When did people talk about PCs more than mainframes? We cannot count tweets or blog posts (neither had been invented) but we can look at magazines and publications. Prior to the IBM PC, most technology magazines discussed mainframes (or minicomputers) and ignored the microcomputer systems. There were some microcomputer-specific magazines, the most popular one being BYTE.

The introduction of the IBM PC generated a number of magazines. At this point the magazine content shifted towards PCs.

There are other measures: number of want ads, number of conferences and expos, number of attendees at conferences and expos. We could argue for quite some time about the appropriate metric.

But I think that the notion of one generation of computing technology replacing another is a slippery one, and perhaps a false one. I'm not sure that one technology really replaces an earlier one.

Consider: We have advanced from the mainframe era to the PC era, and then to the networked PC era, and then to the internet era, and now we are venturing into the mobile/cloud era. Each successive "wave" of technology has not replaced the previous "wave", but instead expanded the IT sphere. PCs did not replace mainframes; they replaced typewriters and dedicated word-processing systems and expanded the computational realm with spreadsheets. The web did not replace PCs, it expanded the computation realm with on-line transactions -- many of which are handled with back-end systems running on... mainframes!

A new technology expands our horizons.

Tablets will expand our computing realm. They will enable us to do new things. Some tasks of today that are handled by PCs will be handled by tablets, but not all of them.

So I don't see tablets replacing PCs in the coming year. Or the next year. Or the year after.

But if you insist on a metric, some measurement to clearly define the shift from PC to tablet, I suggest that we look at not numbers or users or apps but conversations. The number people who talk about tablets, compared to the number of people who talk about PCs. I would include blogs, tweets, web articles, advertisements, podcasts, and books as part of the conversation. You may want to include a few more.

Whatever you pick, look at them, take some measurements, and mark when the lines cross.

And then blog or tweet about it.