Display ad revenue is expected to grow 14.4 percent in 2008, TNS Media Intelligence is forecasting. The numbers further demonstrate the continued health of online advertising considering expectations of a softening economy and relatively anemic ad market. But TNS’ report also provides more evidence of slowing growth, which researchers largely pin on the law of large large numbers. Overall, TNS is projecting 4.2 percent ad revenue growth for 2008, as the Summer Olympics and national U.S. political advertising boost spending, which will be other dampened by the threat of recession.

While TNS hasn’t released its full accounting of 2007, for the first nine months of the year, display grew 17.2 percent to $8.4 billion, the researcher reported last month. And in TNS’ six-month review, that category gained 17.7 percent to $5.52 billion.

As always with TNS’ numbers, it’s important to mention that paid search is not included in its measurements. Having said that, TNS anticipates display’s share of all ad spending will expand slightly, comprising 8 percent of the pie for both 2007 and 2008 combined, behind newspapers, which should claim a 17.2 percent share during that same 24-month period. During the first nine months of 2007, display captured 7.7 percent of total ad expenditures. Release

• Ad Spend Up 15.9 Percent Through September, Slowing Considerably From Last Year: ReportDisplay Ad Revs Rise 17.2 Percent In 2007’s First Nine Months; Growth Rate Slows: Report