KDE Identity considers the privacy of the information stored in it to be very important.
However, in order to allow you to use Identity login enabled sites, some information must be shared with those sites. This usually includes your username, full name and primary email address. The shared information may be stored by the site in question, and it may provide access to it under different conditions.
Information will be made accessible to others by Identity itself based on both your group membership and their group membership. Access to information compounds, so a person may recieve access to information from multiple groups they are members of.