A review of the Top 10 websites listed here indicates there is almost no representation of the diverse racial and ethnic groups beyond white, although they seem to be gender balanced.
The respected Pew Research Center provides these recent statistics:
Nine in ten Americans use the Internet.
Internet usage is equal for White, Black and Hispanic groups.
A broadband connection in Black and Hispanic homes (50%) is less that White homes (75%), but significant.
Use of social media is similar for Whites, and Hispanics, 65%, while slightly lower for African-Americans, 56%.
Use of smartphones for online access is more common among non-Whites.
Are marketing websites that do not make allowances for ethnic and racial groups missing a significant part of their potential market?