There is very little uniformity among the various states of the United States of America on the subject of archives and especially on the subject of what is put online and available in digital format. Here was an interesting note from the Maine State Archives:
This is a screenshot of the Maine.gov website for the Division of Public Health Systems, Maine Center for Disease Control and Prevention, Data, Research, and Vital Statistics -- Vital Records.
So, obtaining vital records copies in Maine is severely limited. Genealogists are required to register. Here is a quote from the Questions and Answers page.
Effective July 12, 2010, all individuals requesting copies of these records must present positive identification and, if requesting the record of a parent or grandparent and you are not a registered genealogist, proof of direct lineage.
Registered genealogists may only obtain a non-certified copy of a record, unless they can meet the above requirements for obtaining a certified copy. They may only view or obtain a copy of a birth, death, or marriage record.
Birth records 75 years or older, marriage records 50 years or older, death records 25 years or older and fetal deaths 50 years or older are considered public records and informational copies can be issued to anyone requesting them.It turns out that some of the records are available on FamilySearch.org in the Historical Record Collections. See Maine Vital Records, 1670-1921. Additional records are available on Ancestry.com, MyHeritage.com and on Findmypast.com.
Digital Maine has an online collection that includes approximately 95 million pages of official state records, maps, photos and donated documents.