The thing is (and this is not meant in any way to be a criticism of the OP) your business model MUST be able to sustain itself outside of search engine traffic to be viable in the long term. If you're just in it for what you can grab while the SERPS are good, and you know going in that it could change at any point, that's one thing. But if you want to build something that's going to last, you have to take a good long look at what you're doing, ask yourself what would you do tomorrow if Google, MSN and/or Yahoo tossed you completely out of their indices, and develop plans for that contingency. It may mean altering your marketing, it may mean adjusting your line of products or services, and it may mean making some staffing or even lifestyle changes. But if, after review, you figure you can't in any way survive without Google traffic - then you have a pretty big problem.