Someday, we’ll tell our grandchildren how we had to drive around town looking for a coffee shop when we needed to get online, and they’ll laugh their heads off. Every building in America has running water, electricity and ventilation; what’s the holdup on universal wireless Internet?

Getting online isn’t impossible, but today’s options are deeply flawed. Most of them involve sitting rooted in one spot — in the coffee shop or library, for example. (Sadly, the days when cities were blanketed by free Wi-Fi signals leaking from people’s apartments are over; they all require passwords these days.)

If you want to get online while you’re on the move, in fact, you’ve had only one option: buy one of those $60-a-month cellular modems from Verizon, Sprint, T-Mobile or AT&T. The speed isn’t exactly cable-modem speed, but it’s close enough. You can get a card-slot version, which has a nasty little antenna protuberance, or a U.S.B.-stick version, which cries out to be snapped off by a passing flight attendant’s beverage cart.

A few laptops have this cellular modem built in, which is less awkward but still drains the battery with gusto.

But imagine if you could get online anywhere you liked — in a taxi, on the beach, in a hotel with disgustingly overpriced Wi-Fi — without messing around with cellular modems. What if you had a personal Wi-Fi bubble, a private hot spot, that followed you everywhere you go?

Incredibly, there is such a thing. It’s the Novatel MiFi 2200, available from Verizon starting in mid-May ($100 with two-year contract, after rebate). It’s a little wisp of a thing, like a triple-thick credit card. It has one power button, one status light and a swappable battery that looks like the one in a cellphone. When you turn on your MiFi and wait 30 seconds, it provides a personal, portable, powerful, password-protected wireless hot spot.

The MiFi gets its Internet signal the same way those cellular modems do — in this case, from Verizon’s excellent 3G (high-speed) cellular data network. If you just want to do e-mail and the Web, you pay $40 a month for the service (250 megabytes of data transfer, 10 cents a megabyte above that). If you watch videos and shuttle a lot of big files, opt for the $60 plan (5 gigabytes). And if you don’t travel incessantly, the best deal may be the one-day pass: $15 for 24 hours, only when you need it. In that case, the MiFi itself costs $270.