We as marketers need three big contenders duking it out. As it stands, Google has 66.1% of the search market (Sep/10/2010). Yahoo/Bing have a combined 27.9% which would leave "other" to account for 6%.
The recent Bing/Yahoo advertising merger means they now account for a third of the market. That's a healthy competitor.
If/when Facebook enters the market, I think they will take a chunk out of Google's market share. Yahoo and Bing will lose share too, but the largest percentage loss will come on Google's end. This will create a "big 3" dynamic.
Facebook is uniquely poised to take on Google (and search in general). Simply adding to their current search feature will guarentee an significant market share right off the bat. Hardly any advertising required. Secondly, they already have a potentially killer organic ranking metric, being the "like" button. The number of likes a site gets will be similar for ranking purposes as Google's link/PR algorithm. It has a lot of potential.
Anyway, I wanted to open these possibilities up for discussion and debate. Do you all think this will be a net positive for markets? Would more competition mean laxer rules by Google AdWords marketers? Laxer rules for direct response marketers in general? Will this be a positive for the end search user?
What do you see being the biggest change assuming a 20% chunk is taken out of Google?