Of course, this is not just about building your cat tree or mounting your TV.

For Amazon it is another step toward becoming the conduit through which we buy everything, not just goods but services and entertainment as well.

“I think it is definitely a very smart move for them,” said Sucharita Mulpuru, an analyst at Forrester Research.

For Google, where a spokesman said the effort was still in early stages, it is a chance to move beyond the advertising dollar to become part of the transaction itself, and to challenge Amazon more directly, as it is already trying with shopping and delivery services like Google Express.

“A lot of commerce begins with Google and has for the last decade,” said Arun Sundararajan, a professor at the New York University Stern School of Business. “They have converted this into an incredibly profitable advertising business. But I’ve seen them make steps to get closer to the actual retail process.”

Still, challenges loom large, and Ms. Mulpuru noted that it had been hard for start-ups to get traction. “Other than Angie’s List, there really hasn’t been, I think, a true competitive player in this space.”

In the case of Ms. David’s faucet, Amazon got the business — as it has with so many of her transactions over the years. In fact, the company’s playbook unfolded perfectly in her situation.

When Ms. David discovered her faucet was leaking, she did what many in her situation would, she used Google to search for plumbers in her area. This would be Google’s opportunity to come in and facilitate the transaction, analysts say. She found recommendations on Yelp and in New York magazine. She made calls, left voice mail, waited, and eventually spoke to a plumber who gave her a convoluted price estimate, she said.