Lead author Lisa Jones of the University of New Hampshire Crimes against Children Research Center suggested greater public awareness may have contributed to the decline.
The study, published in the Journal of Adolescent Health, found the percentage of youth receiving unwanted online sexual requests declined from 13 percent in 2005 to 9 percent in 2010, while youth experiencing unwanted pornography exposure declined from 34 percent to 23 percent during the same period. However, youth reports of online harassment increased slightly from 2005, from 9 percent to 11 percent.
The study is based on national surveys of youth ages 10-17 conducted in 2000, 2005 and 2010.
"The constant news about Internet dangers may give the impression that all Internet problems have been getting worse for youth but actually that is not the case," Jones said in a statement. "The online environment may be improving."
Jones pointed out that unwanted sexual solicitations are down more than 50 percent since 2000, when attention first was drawn to the problem.
"The arrests, the publicity and the education may have tamped down the sexual soliciting online," Kimberly Mitchell, an assistant professor of psychology at the UNH Crimes against Children Research Center, said. "The more effective safety and screening features incorporated into Web sites and networks may have helped reduce the unwanted encounters with pornography."