However, when major disasters happen, the process of learning from them is often ad hoc.

CNN: America isn't ready for superstorms

Better targeting through audio and image recognition could also improve the click-through rate of videos, or how often an ad is clicked for every time it appears.

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However the issue with contextual advertising is that web publishers often sell out ad slots on their popular pages while a majority of their site remains unused.

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The Groupon Web page for first-time users features an image of two cocktails, and its ad copy often touts that drinks like margaritas, ouzo or beer are included in the deal.

FORBES: Focus

By the end, Clinton was operating at half-strength: In most states, Obama had double or triple the field offices she had and often four to five times the ad budget.

CNN: Analysis: Why Clinton's bid failed

It provides good ad targeting to advertisers, consumers often find keyword ads relevant to their interests, and (as I explain here) cost-per-click (CPC) keyword advertising nicely shares the risks of ad performance between advertisers and publishers.

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These firms advise companies how to design their sites to rank higher in search results or to bid more wisely on ad keywords or craft ad copy that will get clicked on more often.

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While companies often want consumers to know about their efforts, few are launching ad campaigns to avoid any criticism of their intentions.

WSJ: Cause-Related Marketing Requires Care

Mr. SETH STEVENSON (Ad critic, Slate online magazine): When I review ads, I often face an obstacle.

NPR: Ad Report Card: Apple's Sour Mac Pitch

Soon MySpace's ad salesmen will use software that sifts through its members' profile pages and sorts them based on the often piercingly personal information they pin up on their pages.

FORBES: Magazine Article