I really enjoyed this presentation from Drew Houston, CEO of Dropbox, an online storage service I've been using for many months now. It covers what they learned on their rapid ascent to success. Among them is the fact that most of their customers have been acquired via referral. Example in point: my endorsement here.
I liked this quote:
SEM is a way to harvest demand, not create it.
That's something that may be evident to those who've purchased AdWords on Google before, but it may not be to the newcomer to SEM. If a user is doing a directed search on Google, it will take a hell of a lot more than a short headline and two line text ad to pry them away from their mission. If your result matches what they're searching for, great, but you can't generate much emotional appeal in two lines of text.
When Apple debuts it's iAd product on the next iPhone OS, you can be sure they'll have worked with some advertisers to debut some eye-popping, emotional, beautifully designed ads. A quick look back at Apple's ad campaigns, from 1984 to Think Different to "I'm a Mac" to its iPod silhouettes, is ample evidence that Apple knows emotional advertising. In their rivalry with Google, it makes sense that Apple would attack Google's core revenue product by differentiating its product on the dimension of design and emotion.
Can your product, in two lines of text in a Google ad, be exactly what a user is searching for? Or does it require sight, sound, and motion to explain what your product is and what it does? Or is your product good enough to mobilize an army of evangelists? It helps to answer that before you choose where and how to advertise.