The 125 x 125 square format has quickly emerged as one of the most popular advertising formats on the web. You’ll notice that many of the most popular blogs out there are using the format, mostly in the sidebar, as a means of grabbing some extra advertising revenue. It’s also the format used by traffic exchange programs like Entrecard.

If you’ve been thinking about selling 125 x 125 ad squares on your blog, but don’t want to deal with the actual management of selling and maintaining those ads as much, this new WP125 WordPress plug-in just might be the ticket. There are other plug-ins out there that offer similar functionality, like the UBD Block Ad plug-in, but WP125 comes with a couple of extras.

Perhaps the two most notable features of this WordPress plug-in are the fact that you can set the expiration date on a given advertisement and you can track the number of clicks that it is generated. This first point makes it easy for you to sell ads throughout the month, not having to worry about taking down an ad after it has expired; the plug-in will do this for you. The second point can help you sell more ads in the future, because you’ll get a better sense of what kind of return the advertisers are getting.

For more on WP125, check out the official page on WordPress.org.