SAN FRANCISCO, July 18 — Meg Whitman, chief executive of eBay, has repeatedly vowed to improve usability of the auction site by redesigning its home page, being more aggressive in combating fraud and improving the usefulness of search engine results.

But while profit was up 50 percent and revenue growth was strong in its second quarter, the company revealed in its most recent financial report Wednesday that it is still struggling to draw more customers. The number of listings on eBay fell 6 percent from last year, and the number of active users is stagnant at 83.3 million, the same as last quarter.

Ms. Whitman said that her efforts to improve the user’s experience should address these problems.

“In the next six months,” she said, “you will see more changes to eBay than you have in the last two or three years, whether that is an improved search experience or fun things that make the site better, like Bid Assistant, which allows you to bid on more than one item without worrying that you will end up buying five iPods by mistake.”

Over all, it was a strong quarter because the total value of sales on the site was up 12 percent from last year, to $14.46 billion, and it was getting more revenue from ads on its core marketplace site.

It reported that net income grew 50 percent, to $376 million, or 27 cents a share, from the period a year ago. Sales rose 30 percent, to $1.83 billion.

Ms. Whitman said that “this was one of our best quarters in the last several.”

The earnings beat Wall Street estimates, and eBay slightly raised its outlook for the year, saying it expects sales of $7.3 billion to $7.45 billion, up from a previous projection of $7.2 billion to $7.45 billion. It also said that earnings per diluted share were expected to be in the range of $1.34 to $1.38 for the year, up from $1.30 to $1.34.

Investors greeted the news, announced after the markets closed, with less enthusiasm. In after-hours trading Wednesday, the stock closed at $33.42, down 1.9 percent. In regular trading, shares closed at $34.05, down 20 cents.

“Remember, the stock had increased 10 percent or so going into the quarter,” said Aaron M. Kessler, a senior research analyst at Piper Jaffray. “The last couple of weeks people had increased their expectations, so these results just confirmed that.”

The company’s efforts to improve usability appear to have yielded some early fruit. In eBay’s core marketplace, revenue totaled $1.29 billion, which represented a growth rate of 26 percent over the second quarter of 2006.

Revenue from the PayPal unit, which faces competition from Checkout, a service from Google, grew 24 percent, to $454 million. In the last month, two airlines, Northwest and Southwest, have said they will accept payments via PayPal on their Web sites.

Google also has designs on the huge e-commerce market. Ms. Whitman said Google was both a significant partner and a competitor, but she said eBay was rethinking its advertising allocation on Google and considering a greater emphasis on offline marketing.

The transition makes sense, Mr. Kessler said. “People who are using Google are probably already on the Web and going to eBay,” he said, “whereas more TV and outdoor advertising might get new users. I think they are looking to diversify.”

Last month, eBay temporarily stopped buying keyword advertising on Google, the Web’s largest search engine. EBay said the suspension did not have had significant effect on its bottom line. “We learned a great deal from that test,” Ms. Whitman said. “It actually had no impact on the financials of the quarter, and we learned a lot about where we want to spend money and where we think we can save money on Internet marketing.”

The Internet phone service Skype, which eBay acquired in 2005 for more than $2.6 billion, continues to contribute relatively little revenue. EBay said that Skype brought in only $90 million during the quarter, though its user base grew 94 percent from last year’s second quarter and now totals 220 million registered users.

Benjamin Schachter, an analyst at the financial services firm UBS, said that Wall Street assigns no value to Skype.

“If you look back at the original rationalizations they gave for the acquisition, none of them have really worked out,” he said. On the other hand, that means any unexpected revenue Skype contributes can only help eBay’s outlook.

In the interview, Ms. Whitman also addressed another recent initiative that surprised some eBay followers: opening a classified advertising site in the United States, called Kijiji.com, to compete with the well-established Craigslist, a San Francisco venture in which eBay holds a minority stake. EBay started Kijiji overseas in 2005.

“We’ve had a great relationship with Craigslist, and we have learned a lot from them,” Ms. Whitman said. “We felt this market was large and diverse enough to support many players. We don’t think of new offerings as competitive, we think of them as better and more choices for consumers. We think there is an opportunity to stake out a slightly different buyer.”