WebProNews

The economic slowdown in the U.S. is starting to impact the online advertising industry, with overall monetization down 23 percent according to ad optimization company PubMatic's second monthly Adprice Index.

The index is based on data from more than 3,000 publishers and billions of ad impressions.

Large Web sites performed the worst while small Web sites were able to maintain their monetization rates. eCPMs (effective cost per thousand impression) for large Web sites (more than 100 million page views per month) dropped significantly by 54 percent from 38 cents in March to 18 cents in April

Medium Web sites (1 million to 100 million page views per month) were almost flat, with monetization sliding from 34 cents in March to 33 cents in April. Small Web sites were able to improve their monetization, increasing from $1.18 in March to $1.29 in April.

Social networking led the way in the decline with monetization falling 47 percent, from 37 cents in March to 19 cents in April. Entertainment monetization fell 17 percent from 40 cents in March to 33 cents in April. Gaming and sports were down 4 percent and 5 percent, respectively.

Technology stayed relatively flat at 83 cents in April compared to 82 cents in March.

In April, 77 percent of small Web sites collected net publisher eCPMs from ad networks of under $1, compared with 95 percent of medium Web sites and 100 percent of large Web sites.