SAN FRANCISCO — EBay, once the online equivalent of a garage sale, is successfully transforming itself into a dominant force in mobile retailing, as seen by the successful turnaround of its Internet marketplace business and double-digit growth of PayPal, its online payments system.

EBay reported Wednesday that it more than doubled net income in the second quarter to $692 million, or 53 cents a share, a 144 percent jump from the quarter a year earlier.

The company said revenue climbed 23 percent, to $3.4 billion, slightly higher than the $3.36 billion Wall Street analysts expected.

John J. Donahoe, eBay’s chief executive, attributed those numbers to the successful turnaround of the company’s marketplaces business, which delivered $1.8 billion in revenue last quarter — its highest quarterly revenue ever — and the continued growth of PayPal.