New twists on old ideas are all the rage.

Everyone is agog at the things that can be delivered directly to their home these days. That’s kind of funny, seeing as I remember when I was very small my mother regularly ordered numerous items from Marshall Field’s, the long-departed and wonderful department store in Chicago and its suburbs. Home delivery didn’t so much get invented recently as rediscovered—and improved.

Riding bikes around urban centers is an exceedingly old idea too. Smartphones and oodles of capital are reinventing that environmentally positive idea. Motivate, an offshoot of the real estate giant Related Cos., runs docking-station-based share bikes in a handful of U.S. cities, including San Francisco, where I’m a satisfied customer. (Motivate makes part of its money from advertising; Ford is the Bay Area sponsor; Citi slaps its name on bikes in New York.)

A new competitor is blanketing North America, Ofo, the Alibaba-backed (BABA) Chinese bike sharing company. Ofo is locked in a battle with Tencent-backed Mobike in China, a proxy war with capital as the weapon and data as the prize. In the U.S., Ofo is expanding far more rapidly. According to Uber veteran Chris Taylor, head of Ofo’s U.S. business, the company already is in more than 12 U.S. cities and will be in more than 100 by next year. Its first city, Dallas, will have 10,000 bikes by New Year’s Eve.

I met Taylor Monday in Ofo’s U.S. headquarters in San Francisco, where Ofo doesn’t operate yet, the result of an exclusive contract Motivate signed with the city. I use “headquarters” advisedly: Ofo currently is housed in a WeWork office, itself a reinvention of an old concept, shared office space. I’ve known about WeWork, but visiting one of its locations was an epiphany. Various-sized workspaces are carved elegantly out of a giant floor. (Time Inc., which will go away soon, had an entire floor in the very same building for many years.) Tenants pay for conference-room time with chits that come with their rent. It’s hard to imagine any company below a certain size going to the trouble of leasing commercial real estate again.

The best new ideas improve on tried and true old ideas. That’s a form of innovation with real commercial opportunity.