Exemptions
There are a number of exemptions under the Act, which include national security, crime, taxation, health records, and aspects of journalism. An important exemption relates to family records, which if not present would require one to register for one's private household records.
Rights and Recourse
You can request the data held on yourself and the purposes to which it is being put. Such a request has to be in writing (which includes email). The data controller is bound to respond within a reasonable time and the response has to be clear and understandable. Bodies holding such data have the right to make a modest charge to service the request and they have limited options to refuse.
An individual has the right to stop direct marketing that is reinforced by EU regulation regarding electronic communication. There is also an entitlement for individuals not to have decisions made about them by purely automated means. Anyone unable to get a satisfactory response from a data controller to resolve an issue can go to court or ask the Information Commissioner to issue an enforcement notice.