The search engine was ordered by a US high Court to unmask the blogger after the model in question, Liskula Cohen, took legal action against Google to discover who made the defamatory comments about her.
In a bid to keep her identity anonymous, Port told the US Judge presiding over the case that blogs were a "modern-day forum for conveying personal opinions, including invective and ranting".
However the Judge rejected her claims and ordered Google to hand over Port's email address and the IP address from which she had logged on.
This information allowed Cohen to discover Rosemary Port was behind the comments. Cohen decided not to continue legal action against Port but despite this Port is now suing the search engine for $15m for breaching "its fiduciary duty to protect her expectation of anonymity".
Google said that agreeing to the terms and conditions of Blogger, means users are aware that their personal information may be disclosed if required by legal action.
"We sympathise with anyone who may be the victim of cyber bullying. We also take great care to respect privacy concerns and will only provide information about a user in response to a subpoena or other court order," said Andrew Pederson, a Google spokesman.
"If content is found by a court to be defamatory, we will, of course, remove it immediately," he added.
See also: Blog etiquette: Top 10 dos & dont's