The Senators request answers to a list of questions such as whether applicants have the right to correct mistakes on their record or how the firm differentiates between individuals with common names.
They question whether the firm attempts to access restricted data on Facebook by friending them or joining a network. The letter also suggests that Social Intelligence's practice of taking screenshots of social media profiles and pictures may violate the sites' terms of service.
"More troubling than the apparent disregard of these websites’ terms of service are what appear to be significant violations of users’ intellectual property rights to control the use of the content that your company collects and sells," the letter states, noting that pictures taken from sites like Flickr and Picasa are often licensed by the owner for a narrow set of uses.
Update: "We welcome the opportunity to clear-up any concerns Senators Blumenthal and Franken may have about our business," said a Social Intelligence spokesman via email.
This post was updated at 4:34 p.m.