• by Gavin O'Malley  @mp_gavin, October 26, 2011

Nearly three-quarters of online publishers now sell 20% or more of their video ad space through ad networks, according to new research from BrightRoll. Per the video ad network, that represents an increase of two-thirds year-over-year.

Also of significance, publishers are not limiting themselves to one ad network. Rather, among the roughly 100 digital publishing partners surveyed by BrightRoll, more than 75% said they have partnered with three or more video ad networks in the past year.

Why the multiple partners? A full 55% of respondents said this stemmed from a simple desire to increase revenue; 21% wanted to increase fill rates, and 16% said they wanted to sell off remnant inventory.

Although publishers are becoming more accustomed to networks, exchanges remain under-utilized, BrightRoll found.

Half of survey respondents said 5% or less of their inventory is available on video exchanges, while one-quarter of respondents said 5 to 25% of their inventory is placed on exchanges  -- indicating that exchange networks are growing but have not yet caught up to networks.

What factors impacted respondents' decision to work with one ad network over another? Topping off the list, 44% of publishers cited ad fill percentage, followed by 32% who cited CPM rates. That indicates that publishers are most concerned with having their ad space filled at an efficient cost.

Other less frequent concerns included the potential for sales channel conflict -- cited by 15% of respondents -- and 4% who listed integration as a key decision-making factor.

Bigger picture: as digital video advertising continues to grow, there are still a number of challenges affecting the development of the industry, BrightRoll cautions.

When publishers were asked what factors they believe to be the greatest barriers to the category’s growth, 42% cited standardization and 39% named interruption to user experience.

Notably, the perceived negative impact of lack of advertisers has dropped in the past year -- with 30% of last year's respondents identifying this concern compared to 20% in the current survey.

According to BrightRoll, this reflects the positive growth trend in online advertising, as an increasing number of advertisers are seeking online video ad space. Although a lack of standards was listed as a concern, an overwhelming majority of publishers -- 80% -- reported that they are able to serve VPAID-compliant ads.

This is particularly encouraging, considering that just 61% of publishers in BrightRoll’s 2010 survey reported that their third-party ad serving was VPAID-compliant.