• by Joe Mandese  @mp_joemandese, September 20, 2013

Exchange-based media buys continued to be one of the fastest growing segments of buys processed by the major agency holding companies, according to the most recent data from Standard Media Index. The amount of digital media buys bought through exchanges rose 56% in August (vs. the same month a year ago), according to the data, which is compiled directly from the systems used by four agency holding companies (Aegis, Havas, Interpublic and Publicis) to process their media buys.

That rate of expansion is consistent with the 58% growth rate SMI reported in July, and shows that exchanges now account for nearly 5% of the digital buys processed by big agencies.

While the share of digital ad buys processed through online ad networks did not erode in August (it was flat) as it did in July and year-to-date, it appears that the major shops are shifting some of their online display activity to exchanges as part of an overall push toward programmatic audience-buying.

In either case, display (+18% in August) and overall digital, including email, mobile, social, video, etc. (+16%) continue to be some of the fastest-growing areas of agency media investments.

Like exchanges, video is a red hot area of growth, also expanding 56% in August, and now representing nearly 8% of total digital volume processed by agencies.

In a breakout of video buying released this month by SMI, the data reveals that the biggest single player is long-tail aggregator YouTube (with a 15.3%) share, and not so-called “premium” players like Hulu, the major broadcast nets, or the big video ad networks.

Hulu was the No. 2 player with a 9.2% share of agency video buying volume, followed closely by BrightRoll (9.1%), but the biggest player overall is, in fact, the long-tail: 42.3% of agency video volume was done with smaller players not classified in the “top 10” suppliers.