Facebook users spend more time on the site than other social media site.

Since the inception of internet advertising, the key measurement for advertising effectiveness has been the number of unique visitors to a site. The more unique visitors, obviously the more people reached.

But recently advertisers have been considering time spent on the site. Engagement is the concept that is gaining attraction. If a person is on a site for longer periods of time, there is more opportunity for the consumer to see the ads on that site.

Radio has been using this concept for years. They have emphasized, “time spent listening” as a way of selling the level of loyalty the station has among its listeners. The more the consumer is engaged with the site, the more influence the site has on the consumer.

And one of the chief winners of site engagement is Facebook. Facebook is already the fourth largest site in terms of unique visitors with almost 97 million unique monthly visitors trailing only Google, Yahoo, and MSN. But additionally,according to Nielsen Media Research, the average Facebook user spent 5 hours and 46 minutes on the site in August. Yahoo is just over three hours and AOL about two and a half hours. (See chart below).  As an indicative of Facebook’s growth in popularity, the 5 hours per month spent on the site, is up from an hour and 30 minutes a year ago. The more time a consumer spends on the site the longer they have to be exposed to the advertising that appears on the site.

This is a distinct advantage over sites like Google whose goal is to provide the information requested as quickly as possible.

So as you consider web advertising, one factor to consider is the time spent on the website. The more time spent on the site increases the opportunity for the consumer to actually see the ad, and it provides a favorable environment for the ad because the visitor is more committed to the site. Engagement adds value as an advertising option for advertisers.