All ads, no matter how small, can influence brand awareness. Even in search, being seen is just as important as getting clicks. Being seen generates Brand Activity, which includes direct entries and brand searches. Prospects don't go to a site a search for a brand without previous exposure to a brand. Brand Activity drives the majority of online conversions for B2B and B2C websites.
A high click-thru rate (CTR) limits the number of times an ad is seen -- limiting the ability to build brand awareness. What's worse, CTR-focused ads often don't contain the brand name -- in an effort to inspire clicks. Thus, CTR focused campaigns waste every exposure and assume that branding can only occur via a landing page. Also, this approach is less likely to disqualify non-buyers -- ensuring low quality clicks.