In terms of market share, ReferLocal is clearly lagging behind, losing to Simple AdServer in all segments.
ReferLocal has better usage coverage in more websites categories. Including Business & Industry, Tourism, Travel, People & Society and 3 other categories.
Simple AdServer is leading in Adult, Autos & Vehicles, Motorsports, Computer & Electronics and 3 other categories.
ReferLocal is leading in most countries, including United States and Australia.
Simple AdServer is leading in Canada.