Like other law-abiding background check companies, Intelius depends on public sources. Any information of yours another person could obtain from government agencies, uncover through Google, or unearth via other search engines is likely within Intelius’ reach.
In other words, Intelius doesn’t need your authority to make your personal (albeit non-sensitive) data available for public consumption. Your consent is implied when you applied for a driver’s license, subscribed to a phone service, created an email account, rented an apartment, filed for divorce, and the like.