Matt Mickiewicz spoke on Secrets to Buying Established Websites for Profit at his session at Affiliate Summit.

There are several reasons to buy existing websites. According to Matt, websites are great to buy because you can purchase sites often for less than three times revenue. You get immediate return on your investment and you are often able to sell later for more money.

Sellers are often unable to get their websites to the next level and you can take your experience and turn it into a substantial return with a strong following. Many people end up doubling the monthly revenue in as little as thirty days.

Buying websites gives you the opportunity to buy existing traffic. In most cases, buying an existing website can get traffic for you cheaper than buying Google Adwords.

Some people buy websites to get page rank and send links back to your blog or website.

Often you can buy blogs that aren't SEO'd and by simply adding the right plugins, you are able to get the website producing fast.

Sometimes you can look at the whois and get a phone number to contact the website owners direct. You can also email the owners and it may be several months before you receive a response back. It may take as many as 6 months or more before you hear back from them. Owners will change their minds through time and that can work in your favor.

When you're buying websites, you get to see how other people are building their sites. That way you can take what they are doing and improve what you are doing.

There are dedicated forums  such as Flippa, and others to find websites for sale.

How you evaluate a website for sale is very important. You need to do due diligence. Use tools such as whois, waybackmachine, SEOMOZ,  Check for back links through Google, Yahoo and others to see what kinds of sites link back. That may mean that the owner of the site has bought back links.

Sometimes owners will interlinking between their own sites, they sell one and remove the links. You need to make sure the links are going to stay after the sale.

Make sure the traffic is for the website your buying. Use Google Analytics and check the robots.txt file to see if there is content that they don't want Google to see.

Do an online meeting and have the owner log into all the revenue streams to show where the money is coming from.

Does the owner do Google adwords? If so are they buying adwords to build up traffic.