Live.com, Microsoft's main search property, was the top-gaining site in average minutes spent per day in May compared to a year earlier, with a 445% increase to 16.6 minutes, according to comScore Media Metrix.

An analysis in June Internet Report by media-buying agency ZenithOptimedia explained that the time-spent increase "might be due to the fact that search-only traffic to MSN is progressively migrating to Live.com as Microsoft redefines its search engine brand strategy in an attempt to gain market share from industry leader Google."

Last month, the software giant also rolled out a new, streamlined Live Search interface.

But Microsoft shouldn't be overly encouraged by the Live.com gain in time spent. The same report, citing comScore figures, found that Google's share of searches has grown over the last year to 57.2% from 48.6%. Microsoft's share, meanwhile, has continued to dwindle, to 6.2% from 7.3%.

Google's unique visitors also hit 157 million in May, up from 135 million a year ago, while traffic to Microsoft sites has increased only about a million to 65.4 million. No wonder Microsoft is still trying to work out a deal to bolster its search assets.

In other findings, the ZenithOptimedia study showed AOL was the only top ten Web property to lose ground in both reach and time spent, dipping 5.6% and 0.5%, respectively, in each category. It also joined eBay and Microsoft as the only sites among the top properties losing traffic over the last year, down 5.7% to 80.7 million visitors.

While YouTube remains the dominant multimedia site with 66.2 million visitors in May, users don't appear quite as taken with the video site as they were a year ago. The average time spent was down by almost 16% to 19.5 minutes in May.

Disney Games enjoyed the biggest games among multimedia properties, with traffic tripling to 12.1 million, reaching increasing four-fold to 4.2% and time spent more than doubling to 9.2 minutes.

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