Someone has mentioned that I should have Stumble Upon, Propeller, Digg on my site. Can someone explain (in detail cuz I am an idiot) how Propeller and STUMBLE UPON work. Do I have to change the code they give? Is it worth having? What exactly would it do for me?

As far as I feel it does very little. Basically people click your site and may or may not stumble it. The traffic you get can be huge but the traffic does not convert and most people just click through your site so they do not even have a chance to see and ad. Since quit using them, I have decreased my traffic but now the traffic is more targeted and my earnings increased. The main thing they do are increase your traffic which looks good in stats only. They also increases your bandwidth usage. If you are planning to sell a site, the numbers may look good to a buyer if they do not check to see where the traffic comes from. The codes should be able to be placed right into your site. StumbleUpon needs a free toolbar. First go and sign-up and then install the toolbar on Internet Explorer or Firefox. And then click on the "thumb-up" stumble upon button on the toolbar when you are surfing you website. Propeller needs to get sign-up too. Both are free. And then you will go to "submit new" and you will submit your article or your website.