Bing's big debut continues as Microsoft's revamped search engine gains share in both the number of searches its handled and the number of and paid clicks its raked in during its first week, according to search engine marketing firm Efficient Frontier.

Microsoft (NASDAQ: MSFT) realized a 18.9 percent lift in shares of impressions for the week Bing officially launched, compared to the prior week, while paid click share increased 8.1 percent, according to Efficient Frontier data.

"In our view, if this share lift holds, we can expect advertisers to allocate additional budget to Microsoft over the coming months," Justin Merickel, vice president of marketing and product development for Efficient Frontier, told InternetNews.com.

Microsoft's lift in share of impressions indicates that new users are trying Bing or that existing Microsoft search users are increasing their volume of queries, Merickel said.

He said one possible reason that paid click growth lags behind Bing's search numbers could be due to organic listings in Bing delivering more relevant results.

Bing's new "decision engine" features, such as query-specific subcategories available on the top left of the results page, may be allowing consumers to more easily find a relevant organic result, Merickel said.

Still, he warned that "one week does not make a trend," and that new users may simply be exploring the new search engine out of curiosity following news of the launch.

Yet, the numbers do signal there may be at least some potential in Bing for Microsoft.

"It is undeniable that the needle moved in a positive direction for Microsoft. We'll watch closely as the coming weeks' data tell us whether Bing gains additional traction, sustains the lift of launch, or falls back to prior levels."

With Bing, Microsoft has chosen to concentrate on four areas where it feels it has specific expertise -- shopping, local, health and travel -- in addition to general search capabilities. Searches in those categories deliver extra detail from crawled sites.

Bing's promising early numbers come on the heels of other positive third-party reports, after a bumpy start at launch. According to comScore, Bing in its first week increased Microsoft's search engine market penetration 1.7 percent, from 13.8 percent in a five-day period in May to 15.5 percent during the period of June 2 through 6

On June 4, Bing was the second-place search engine worldwide, according to net metrics tracking firm StatCounter.

Much of the world -- at least the part of it that's interested in search market share -- has been waiting to see whether Bing will actually accomplish what Microsoft has been struggling for over the past several years. That is, to put Microsoft in second place ahead of Yahoo (NASDAQ: YHOO) -- and even to even pose a serious threat to Google's dominance in search.