Google bulks up Gmail with built-in search

Google has added the ability to search Google directly within Gmail, a move that increases the centrality of the e-mail service and gives Google a new opportunity to show advertisements.
The experimental feature, part of Gmail Labs, presents a search box to the left of a message you're composing. Typing search terms in it pops up a miniature window with a handful of results, and an individual result or its URL can be copied into the e-mail message body or into a separate message.
Programmer Adam de Boor detailed the feature last week in a Gmail blog post.
There are two things interesting about this move. First, it reflects the increasing breadth of what can be done in Gmail besides just e-mail. The company has added instant messaging and video chat, which being communication mechanisms are conceptually similar to e-mail, but also through an open-ended gadget interface has enabled links to Google Calendar, Google Docs, and third-party services such as Twitter.
Clearly, Google wants to let people spend more time living within the confines of Gmail.
Second, the feature lets Google show more search ads, the company's bread and butter. To an extent, this is likely a wash, since the same ads would show if a person moved to a separate browser tab or window to run the search, but it's also possible that having a convenient search box will mean that people will search when they didn't before.
Gmail sometimes shows ads to the right of the message body based on the text in the message itself, using the same technology Google uses for its AdSense service, which places ads on third-party sites. Todd Jackson, product manager for Gmail, said the click-through rate for Gmail ads is about the same on Gmail as on third-party sites and that "it's a good source of revenue for us."
However, an April study by Efficient Frontier showed that Google's search ads show much better click-through rates than AdSense ads. That's important, because advertisers pay Google only when a person clicks on those ads. The rate was 2.4 percent for Google's search ads but only 0.2 percent for AdSense ads.