Sydney man Zane Alchin has been given a 12-month good behaviour bond for writing sexually explicit and threatening comments on Facebook.

Alchin, 25, wrote abusive and threatening comments on a post about 25-year-old Olivia Melville.

A friend of Alchin's had taken a screenshot of Ms Melville's Tinder profile and posted it on Facebook, where it was shared thousands of times.

After that, Ms Melville received many abusive online messages from strangers.

Alchin pleaded guilty to using a carriage service to menace, threaten or offend.

Zane Alchin said he was unaware internet trolling was a crime. ( Fairfax Media: Nick Moir )

The court heard he left a large number of highly offensive and sexually explicit messages over a two-hour period.

Magistrate William Pierce said he accepted that Alchin did not incite rape with his comments, but he intended to be offensive and has "already paid for it big-time" suffering a torrent of abuse in return.

Alchin's solicitor Sophie Walsh said her client was intoxicated during the episode and apologised to the target of his abuse the next morning.

She said he was not a troll as he left his name on the postings and was responding to what she described as an online "firefight".

"The irony is that he has become a much greater victim than the crime he committed," she said.

Earlier Magistrate Pierce caused rumblings in the court when he described the women's Tinder profile as containing a "somewhat inflammatory comment of a sexual nature anyway".

Paloma Brierley Newton said the way the case was handled by the magistrate was questionable. ( Supplied )

In giving Alchin a 12 month good behaviour bond, he likened the defendant's comments to being involved in a game of football where a few bumps and bruises are acceptable.

"Your comments were the equivalent of socking someone in the jaw," he said.

Ms Melville today came face-to-face with Alchin for the first time, and said he did not apologise or look remorseful.

She said she was pleased that a conviction had been recorded and relieved that the lengthy ordeal was finally over.

Ms Melville said she hoped her case helped to highlight the fact that threatening people online is a crime.

'Penalty appropriate but judge's handling questionable'

Another woman involved in the online argument, Paloma Brierley Newton, said she accepted the penalty was appropriate but disagreed with some of the magistrate's comments.

Ms Brierley Newton came to Ms Melville's defence on the Facebook thread and herself became the target of sexually violent comments from Alchin.

Paloma Brierley Newtown (centre) with her supporters after the decision. ( ABC News: David Spicer )

"My reaction is that we got the result that I think was appropriate to the situation. The way that it was handled by the judge is questionable," she said.

"The fact that he (Alchin) said raping a feminist was better because they're 100 times tighter is disgusting. The fact that he can get away with saying that because he had half a bottle of bourbon at 11:30am is disgusting.

"I hope that we set a precedent to men that we have to stop putting women down. Punching down is not ok.

"I've never seen an apology from Zane Alchin. I've never heard an apology from Zane Alchin.

"All I've seen him to do is flip the bird at the media. All I've seen him do is attack the media and incite the media. All I've seen him do today is stare me down every single second he got the opportunity."