Frequently, this is because some can't remember their account name or password. Sometimes, this is because they have an account name that they can't change, because they don't realise the connection between the email address and the account name. And occasionally, this confusion leads to worse problems, such as inadvertent creation of additional accounts.
A Blogger account is simply a Google account, used to access or to manage blogs. A Blogger account is setup on the fly, when you create a blog, or when you accept membership in someone else's blog (in an ownership transfer, as a new author, or as a designated reader).
Google accounts are based upon email addresses. This is the basis of Google account uniqueness - and the source of some confusion.
Many Google accounts are based upon GMail addresses, but this is not a necessity. A Google account can be based upon any email address that you wish.
- You can setup a Google account based upon any GMail, or non GMail, address - and you can use the same password, or a different password.
- If the account is based upon a GMail address, Google will validate the GMail address and password. Here the password used by GMail will be equal to the one used by Blogger - since it's the same Google account.
- If the account is based upon a non GMail address, no validation is done - Google simply creates a new non GMail based account (when that non GMail address has not been used, in the Google accounts database), using the "email address" and password provided.
- The password used for the new Google account may, or may not, be equal to the password used in the original non GMail email account. You are responsible for ensuring (at your discretion) that the "email address" is valid - and that the passwords are identical, or different. And, you are responsible for remembering each account name and password.
- Note that the term "non GMail based Google account" may not be applicable to email accounts based on Google Apps provided custom domain email domains. These accounts are GMail accounts - and use one account name and password stored in the Google database - even though they do not include "GMail.com" in the account name.
- When a membership invitation is accepted, the email address used may, or may not, be the same as the email address specified in the Permissions list. The address used by the blog owner is at the choice of the blog owner. The address used by the new blog member is at the choice of the new blog member. The new blog member has the final choice.
- Once a Google account is setup, with the name of the account based upon an email address, that name can not be changed. If you want to use a different name for your Google account, you must setup a new Google account (using the email address of your choice), and transfer resources (such as Blogger blogs) to the control of the new account. Some resources, such as Picasa accounts, cannot be predictably transferred.
- You can change the email address associated with any non GMail based Google account, at any time. This will change the email address used for backdoor authentication. The account name will not change.
- A Google account based upon a non GMail email account is completely separate from the non GMail email account.
- If you change the password on the non GMail email account, don't expect for the password on the Google account to change, automatically.
- If you forget the password, and have the non GMail email account reset (by whatever backdoor is provided by the non GMail account provider), you'll next have to reset the password on the Google account, using the non GMail email account - if you wish for both passwords to remain synchronised.
- If you rename the non GMail email account, don't try to rename the Google account - though you can, and should, change the email address.
- A Google account, based upon a recently deactivated non Gmail email account, continues to be valid - as long as you can remember the password previously given to the Google account. As mentioned above, the password may - or may not - be the same as the password used for the non Gmail email account.
- If your non GMail email account is discontinued, it is in your best interest to update your Google account(s) and change the email address associated with those account(s), to a working email address that you can use. This will enable you to later change the password associated with your Google account, should you forget the password.
- When we first load a blog, then second sign in to Blogger, we are expected to reliably identify both the account and the password, which we intend to use. The Blogger sign in wizard does not identify the owner account for the blog being displayed, and allow us to sign in with that account.
- Since Blogger promises protection of our blogs, and promises us that our blogs will be ours forever, they can't, legally, give us backdoor access to our blogs, when we casually forget the password, and the email account used for backdoor access is inactive / unavailable. That policy protects my blog - and yours - from people who would steal my blog from me - or your blog from you.
- Accounts setup when accepting membership in an existing blog present still more possibilities for problems. Here, Blogger wants to make it easy for existing bloggers to accept memberships, and authentication standards will be different.
- GMail Support provides simple procedures for recovering control of lost or stolen GMail accounts. Some of the procedures may, or may not, be useful in recovering control of our Blogger accounts and our Blogger blogs.
These details, which might appear arbitrary, irrelevant, and / or trivial to the average blogger, are neither. Each detail is based upon how Blogger and Google authenticate their users, and are predictable based upon (generally) standard practices in Information Technology. And these details, taken in various combinations, can cause non trivial results, which lead to many of the more challenging problem reports in Blogger Help Forum.