This really isn't an advertising model. It's a bona fide thank-you to Stack Overflow members from our friends at Telerik.
I mean, let's think about it. It's a promotion that's precision-targeted to an extremely small number (250?) of members (many of whom are not even .NET developers) to give away a product? Where's the money in that? Hoping that a handful of ~250 somewhat-influential people happen to recommend the product to someone else? As far as business/marketing plans go... this is certainly not one.
As I noted elsewhere,
The 10K-targeting was a very special thing that we did exclusively for Telerik, as they are a very special sponsor. But at this time, we are not offering rep-targeting for anyone else. Once we see how this promo goes, then we may consider offering it to other premium sponsors.
So depending on the demand (and if we think the readers would find it a good fit), we may do another thing like this in the future... but it's never going to replace standard advertising.
Spending money on advertising (when done right) will bring in more money. Giving away the whole enchilada to a small number of people (no matter how you do it) will not.