Nielsen//NetRatings has announced the leaders in three Web categories. Search, career development and multi-category travel have had high month- over- month visitor retention rates from June to July, but also had audience overlap with other competitors in their categories.

Search providers had the best retention rates, with an average of 71 percent of June visitors at home retuning in July among the three most popular search engines. Google search led with a retention rate of 79 percent, Yahoo Search was second at 69 percent and MSN/Windows Live Search had 65 percent. Visitor retention rates were a little higher with the work audience, who had an average of 76 percent among the three leading search providers.

Nielsen noted that a large portion of visitors went to more than one of the three search sites in July. MSN/Windows Live Search had the highest audience overlap with 84 percent of its unique visitors also going to Google, Yahoo or both. Yahoo had a 78 percent audience overlap with Google and MSN. Google had a 63 percent audience overlap with one or both of its competitors.

"These search providers are doing a good job of bringing their visitors back month after month, which is an important sign of the health of their customer relationships and a measure with significant financial implications, given the expense of acquiring new customers," said Ken Cassar, chief analyst, Nielsen//NetRatings.

The most popular three sites in the career development category were CareerBulider, Monster and Yahoo HotJobs. They had an average month- over- month retention rate of 38 percent at home and at work it was 44 percent. Monster.com had the most audience overlap with the other two, at 50 percent. Yahoo had a 45 percent overlap, while CareerBuilder was 34 percent.

The top sites in the multi-category travel, Expedia, Orbitz and Travelocity, had the lowest average month- over- month at home visitor retention rates at 31 percent. At work it was a little higher at 35 percent. Overlap was similar between the three sites at 59, 58 and 51 percent for Orbitz, Travelocity and Expedia, respectively.

"Search is a daily online activity for most Web users, so search providers can rely to a certain extent on frequency of use as a driver of repeat visitation," said Cassar.

"Career development and travel sites are used less frequently, so their challenge is to be top of mind when it comes time to look for a new career opportunity or plan a trip."

Search Engines Travel Sites