According to a proposed US Senate Bill, bloggers are journalists:
One of the biggest issues is just who is a journalist, or in the phrase the bill uses, a "covered person." Once that definition is clarified -- and even Judiciary members say it's not settled -- a journalist would under most circumstances not have to disclose to federal authorities or in civil lawsuits the identity of sources who have been promised confidentiality. Also protected will be records, communications, documents or other information that this "covered person" receives from confidential sources, as well as notes the journalist makes of conversations with these sources.
The Senate committee bill employs a broad definition: A "covered person" is someone "engaged in journalism," which itself is defined as "the regular gathering, preparing, collecting, photographing, recording, writing, editing, reporting or publishing of news or information that concerns local, national, or international events or other matters of public interest for dissemination to the public." That would cover those working for major news organizations as well as individuals putting out their own blogs or newsletters.