Entrecard???

Entrecard is the first and only free exchange network for 125x125 ads. Through this revolutionary platform, you can advertise your own 125x125 Entrecard on any blog in the network, for free, for a number of days. You pay for this advertising with Entrecard Credits, that you earn for free by networking (a.k.a. visiting blogs and dropping your card for other bloggers).


Dropping your card for someone is completely different than advertising on their widget.
When you drop your card for someone, by clicking 'Drop yours' on the bottom of someone's widget, your card will be displayed in their inbox when they log into the Entrecard. The Entrecard member can click through to visit your site via your card in their inbox. Dropping your card will not make your card appear on their widget or website.

Credits
What are credits?

Credits are the currency of the Entrecard network. You spend them to advertise your Entrecard on other people's widgets.
How are credits earned?
You earn 1 credit every time you drop your card for someone else.
You earn 1 credit every time someone else drops their card for you.
You earn credits every time someone advertises on your widget.

Advertising Costs and Wait Times
How much does it cost to advertise on someone's widget?

To advertise your card on someone else's widget, it costs the number of credits equal to twice the number of cards dropped on that widget each day. So if a widget receives an average of 50 cards dropped into it each day, advertising on that widget will cost 100 credits per day. This helps insure that for every two credits you pay, a unique user will see your ad and be clicking in the general vicinity. It also ensures the economy balances, because every time you drop your card, it creates two credits. That surplus mus be balanced via advertising costs. Advertising spots are awarded in a first come first serve basis, and extend 9 days into the future. So, if 9 people apply to advertise on a specific widget, and the blogger approves them all, no new advertisements will be accepted until one of those ads runs through and expires. You can apply for as many 24-hour advertising terms as you would like until all 9 days of the users advertisement que are filled. The cost to advertise, and the wait time, are both displayed underneath each users card in the Campaign section.

How long do I have to wait for my card to appear on someone's widget after I have applied to advertise?

After you apply to advertise on someone's widget, two things must happen. First, the owner of the blog has to approve it. Next, all the ads that were approved to run before you have to run their course. This wait time is displayed for you underneath everyone's card on the campaign page.

Approving and Rejecting Ads
How, where, and why.

When someone applies to advertise on your widget, you must approve their card before it will display live on your site. You are in full control of the cards that run on your site. You may want to reject cards that do not look professional to uphold your own quality standards. All cards that have applied to advertise on your widget will be displayed under your advertisers column on your dashboard. Underneath each one is an option to either approve or reject them. Approving them will cause the ad to run live once all the other ads approved before it run on your widget. Rejecting the ad will remove it from your advertisers box.

Try it! It's cool! Helps too boost traffic and meet fellow bloggers!!!

http://entrecard.com/