Keeping Top On Google

Update your blog or website to ensure you maintain your position on Google results. A regular post at least once a week will keep the search engines interested. Stop updating - and you risk being slowly relegated down the results.  If you have a post that is doing very well on Google - don't make any changes to it. Add new posts by all means. Keep checking your position on google - to see how you are doing. Things change all the time. The number of hits you get can drop by at least 100% if you drop from top position to second position on Google. Google is the major search engine - if you lose google traffic - the traffic from Live or Yahoo will be a small fraction of the google traffic.
Be careful of duplicating content. I had a new site on it's own domain which I set up to replace an existing blog on a free blogging site. Laziness and haste made me do a lot of copy and past to get the new site up and running while he old site was still online too. I suspect that was the main reason why it appears to have vanished from google after doing very well for a few months. A few attempts to get  it back have failed  - so I will have  to start again.