Do not forget the "Traffic" - 2.

Traffic Swarm is the oldest and the biggest traffic exchange online. With more than 1,000,000 members, it?s by far the most attractive traffic exchange for internet marketers.

Traffic Swarm is a little like a free AdWords program. You set up a campaign, write a short description of your link, and decide how many credits per day to devote to a particular campaign. (You can have multiple campaigns in one account). Every time your link is displayed it costs you one credit.

To get people on a traffic exchange service to click to your website you have click to other members? sites.
Every visit you make to a member site earns you a random number of credits, usually between 1 and 5 but sometimes 0 or 50 or more. The randomness of it gives TrafficSwarm a bit of a casino feel. Indeed, you can use your credits there to buy entries in a daily credit lottery. Clicks to TrafficSwarm members are made within a frame in a separate window (the ?Start Page?) where there?s a 20 second timer. You have you remain on the member site you visit for the full 20 seconds, and then click ?next? to get your credits.

I highly recommend Traffic Swarm, by far the best and most useful free traffic exchange.