Pencils ready, everyone? Here’s your vocabulary lesson for the week.

Phrase of the week:  Advertising (Ad) Network

What does it mean? An ad network is a company that serves online advertisements throughout numerous websites.

Ad network inventory can include banners and text links on websites, mobile devices, RSS feeds, instant messaging applications and more. Large publishers often sell their remnant inventory to ad networks when their advertising sales rep is unable to sell it.

A couple nice aspects of using an ad network: 1) They have a very large reach across the online universe, and 2) The costs to advertise within a network are typically much lower than going to an individual website.

One negative side? Many ad networks are “blind networks” — meaning advertisers relinquish control of where their ads will run. The ads are served across a list of websites that is only visible to the ad network.