Five websites accounted for 20 percent of all search activity during the fourth quarter of 2012, and Facebook sat atop that list, as the subject of 8.48 percent of all searches during the period, according to the latest research from Experian Marketing Services.

Rounding out the top five, according to Experian Marketing Services, were: YouTube, Yahoo, Wikipedia, and Amazon.

Experian Marketing Services said in introducing its 2013 Digital Marketer Report:

Five websites captured 20 percent of all search activity in the fourth quarter of 2012, while the top 500 captured nearly 50 percent. Expansion to the top 1,000 websites reached nearly 75 percent, highlighting the challenges for marketers to reach potential customers through search, even for those with a large Web presence.