Iran has stepped up its campaign to ensure the body of water between Iran and the Arabian peninsula is known as the Persian, not the Arabian, Gulf.
Users who type the words "Arabian Gulf" are in for a surprise
It is said to have withdrawn an invitation to National Geographic magazine to attend a festival because they refer to the Gulf as both.
Iranian bloggers also launched a web action on the Google search engine.
The words "Arabian Gulf" elicit a spoof message: "The Gulf you are looking for does not exist. Try Persian Gulf."
The practice, known as "Google bombing", has been used in the past against George W Bush, who comes up under "miserable failure".
The message parodies the text which usually appears when a web page does not exist, and goes on to recommend that users should read "some history books".
It is the second time Iranian bloggers have united to make a political point.
Earlier this year, they used their weblogs to direct users to pro-reformist websites and online newspapers that had been closed down by the Iranian authorities.
Al-Jazeera under fire
In Tehran, organisers of a photo festival told the AFP news agency they had invited National Geographic's picture editor, Susan Welchman, to join them on the jury for the exhibition's competition, but said she was now no longer welcome.
Iranian officials objected to the fact that the latest issue of the magazine's atlas refers to the stretch of water as "The Persian Gulf (Arabian Gulf)".
National Geographic has already been banned from going on sale in Iran, pending a "correction" of the atlas.
On Monday, Iran threatened the Arabic satellite TV al-Jazeera with action for an online animated cartoon published in the wake of the National Geographic ban.
It shows an Iranian cleric ignoring regional problems in favour of taking action over what to call the Gulf.