Faith + Reason = Truth

Network Effects 101:  people like to go where the other people are when it comes to buying, selling, or communicating.  Right now, that place is Google search.  When you've got something to sell, and you need to set up search advertising, you will reach the most people by setting up shop with Google.  Most people stop there, because even though they know Google isn't the only game in town, they don't want the hassle of setting up shop with the other guys because they figure they'll be found by "most" or "enough" people with their Google search ads.

I think the only way to get these people on board (alongside of, rather than instead of, Google) is to go beyond discounting and even beyond free:  you could actually do it for them.  This would probably be a labor-intensive effort, but if you really wanted to grow your search ad business (and MSFT just spent a quarter of a billion $ to very loudly proclaim that yes, they really want to), you could click on people's Google search ads, land wherever it takes you, send that business an email that says "hey, I've just cost you $.50 by clicking on your add, and to make it up to you, I'd like to build you the exact same ad on OUR search ad network [MSN, Live, Yahoo, whatever] and spot you your 1st $5 worth of search ads on us.  We'll even shoot you an email when the $5 is used up to let you know how many people landed at your destination courtesy of our efforts and expense.  No contract or anything; if you do nothing, your ads on our network will simply stop running at no cost to you [and the people who find you on our network will no longer find you]."

Is there ANY way this tactic would NOT result in a significant increase in customers, since you would have overcome all barriers to their entry into your network with absolutely no cost or labor from them whatsoever?  I can't think of any.