This compares audience composition of the site to the entire Internet population. The higher the index number, the more concentrated a site is in a particular demographic.
As an example, if a site indexes 100 for age 18-24, that means a given visitor to it is as likely to be 18-24 as any internet user chosen at random. An index of 200 means the visitor is twice as likely to be 18-24, 50 means half as likely, and so on.
2. Segments are represented with icons. Segments include gender, age, household income, and education.
3. Very High Indexes (over 200) are denoted with a plus symbol.
4. Internet Average is represented by the dotted vertical line.