Furtune Interactive, a respected marketing company, revealed the results of their study on search engine ranking behavior. The big winner QUALITY in-bound links (quantity is not as important).

Here are is the important factors you need to know:

Google ranks by...

1. Off-Site Optimization
    Order of importance: quality of inbound links, relevance, title keyword, anchor keyword and quantity.

2. On-Site Optimization
    Order of importance: keywords in title, anchor keywords, keyword in the body, general content

Yahoo ranks by...

1. Off-Site Optimization
    Order of importance: quality of inbound links, anchor keyword, title keyword, quantity of links

2. On Site Optimization
    Order of importance: keywords in title, keywords in body, general content relevance

MSN ranks by....

1. Off-Site Optimization
    Order of importance: Inbound links quality, anchor keywords, relevance, keywords in title

2. On-Site Optimization
    Order of importance: Keywords in title, keywords in body, anchor keywords, general content relavence

* Quantity of links are not weighted as much as Yahoo

Note: Yahoo and MSN have recently done updates, so some of these findings may now be sku'd.