Ralph Nader is running for President of the USA

Ralph Nader has thrown his hat in the ring for the 2008 Presidential elections. This will be his 5th time running for President (1992, 1996, 2000, 2004 and 2008) and some say that he was the reason that Albert Gore didn't clinch the Presidency in 2000. What does this mean for the Republican and Democratic contendors if anything? He is probably good for 1-4% of the vote which could just tip the balance of power.
This is already an exciting race for President, it now gets more interesting. Question of the week....Will Bloomberg also run for President as an independent in 2008?????