It seems a little easy to dismiss the others. It's important to note that Google has only been in business since about 1998 (about ten years). There was life before Google, and there is always an opportunity for a new start-up to crash the landscape or for things to change within the existing space.
Just this week, it was announced that Microsoft had made a $1.23 billion dollar bid for another search engine, Fast.
From understanding the future power of Universal Search to simply acknowledging that more and more Consumers are having their first brand interactions at the search box, it's easy to see why Marketers and Advertisers continue to shift budgets into search. 2008 already looks to be like the best year-to-date for Search Engine Marketing. The old advertising adage of "no one ever got fired for putting television on the media buy" is quickly shifting to, "no one ever got fired for putting search on the media buy."
But, in a world where 20% of all searches done on Google each month are keyphrases that have never been searched before, the challenge for Marketers is to figure out a way to deploy a mass amount of keywords that just "perform," while tweaking the batch that fluctuates all the while looking at that 20% to see what new words can be incorporated. So, as simple as that little search box looks, Search is increasingly becoming more complex and competitive.
You can see the Hitwise information here: Google Sets New High With 66% of US Searches in December.