Houndstooth - 10:22 pm on Jun 1, 2005 (gmt 0)

In the end it comes down to sales, costs and ROI. I've explored probably 5 different 2nd-tier engines with some top software brand names. I have had some success driving a significant volume of sales at a good ROI, so it can work. One engine in particular has bent over backwards to help me hone in on those sources of traffic that are generating the highest ROI.

Other notes:
1) The traffic appears to be fairly incremental to Google and Yahoo.
2) I've seen ROI to be about half that of Google on a similar keyword list (so 10x ROI on Google is ~5x ROI on a good 2-tier).
2) Adding multiple 2-tier engines quickly cannibalizes each other, meaning there's a high degree of overlap of traffic relationships. I've tested out various combinations of engines to see where the optimal point is.

The funniest moment for me came when a sales rep called to pitch me on their listing solution, and I asked him to walk me through their site with links to all of their traffic relationships. Every listing I went to, had listings from some other 2-tier engine! It was comical to hear him try to explain the value of his service. He still hasn't gotten back to me....