Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.

Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and password).

SharePoint-based Web sites can be password-protected to restrict access to registered users, who
are invited to join via e-mail. In addition, the site administrator can restrict certain members' roles
by assigning different permission levels to view post and edit.

An internet site is a normal site that anyone on the internet can access (e.g., www.msn.com, www.
microsoft.com, etc.). You can set up a site for your company that can be accessed by anyone
without any user name and password.
An intranet (or internal network), though hosted on the Web, can only be accessed by people who
are members of the network. They need to have a login and password that was assigned to them
when they were added to the site by the site administrator.

If the users sharing that login will have the same permissions and there is no fear of them sharing a
password, then yes. Otherwise, this is discouraged.

An authentication mechanism in which a Web application authenticates itself to a Web server by sending the server a message

digest along with its HTTP request message. The digest is computed by employing a one-way hash algorithm to a concatenation

of the HTTP request message and the client's password. The digest is typically much smaller than the HTTP request and doesn't

contain the password.