Internet usage in the United States appears to have picked up again in May after an April decline that worried many Internet stock analysts, according to data released this week by Nielsen/NetRatings Inc.

The number of people who visited the Internet's top sites rose 8.7 percent in May compared with April, after dropping 4 percent the previous month, the company reported. The average time spent on each site jumped by 24 percent, from 29 minutes in April to 36 minutes last month.

The number of people in the United States who went online at least once in May rose nearly 7 percent, to 101 million. It had declined slightly--by about 1 percent--from March to April, NetRatings reported.

The United States has the largest online population in the world--about one-third of the nation's homes are plugged in--and analysts closely watch the monthly usage numbers as a barometer of how fast the remaining two-thirds might adopt the new technology.

NetRatings analyst Allen Weiner speculated that spring fever drove people outside and away from their computers in April, but planning for summer vacation brought them back online in May. Travel sites registered a 16 percent increase in traffic in May, while general shopping sites had average traffic rises of 14 percent. News and entertainment sites were up only by 7 percent, the company said.

"I also believe we are seeing tremendous competition now between hardware manufacturers promoting their sub-$1,000 computers," Weiner said. "That price point may be bringing new Web users into these categories."

May Traffic Patterns on the Web

Top e-commerce Audience Average time spent at site

sites size

1. Amazon 6.4 million 15 minutes, 50 seconds

2. EBay 5.4 million 2 hours, 42 minutes, 45 seconds

3. CDNow 2.0 million 15 minutes, 56 seconds

Sites with the largest increase in unique visitors from April to May:

1. "Star Wars" official site 179%

2. World Wrestling Federation 83

3. HomeArts 67

4. Rolling Stone 65

5. 39

SOURCE: Nielsen/NetRatings