• by Wendy Davis  @wendyndavis, June 17, 2005

In the last year, telecoms have increased their share of online advertising, while marketers in Web media, financial services, and retail goods and services now account for a smaller proportion of online ads, according to new data from Nielsen//NetRatings.

Last month, telecoms accounted for 13 percent of online ad impressions last month, up from 8 percent in May 2004. At the same time, Web media ads accounted for 20 percent of all May impressions--down from 22 percent a year ago--while financial service marketers were responsible for 18 percent of all online impressions--compared to 19 percent one year ago--and retailers accounted for 14 percent of online ads, down from 15 percent last May.

Overall, marketers across a variety of industries delivered 93.1 billion impressions in May--up from 91.4 billion in April, but still down from the 97.1 billion served in March.

Among telecom advertisers, Vonage Holdings Corp more than tripled its share of impressions to 24.5 percent last month, from 7.2 percent a year ago. Online ads from Verizon Communications remained steady, accounting for 16.5 percent of impressions--up slightly from 14.9 percent last year May. SBC Communications, Inc. and BellSouth Corporation likewise remained relatively flat: SBC's May share of online ads was 14.6 percent--down slightly from 17.3 percent last year--while BellSouth accounted for 11.3 percent of telecom ads, up from 10.5 percent last year.

The company that most notably decreased its online ads was EarthLink Inc., which accounted for just 2.2 percent of telecom impressions last month, compared to 10.2 percent in May 2004.