According to a report in the Kurier newspaper the most popular item for sale is a camouflage cap featuring a jihadist print and the IS icon.
The Facebook group, set up by an individual who calls himself Muslim Alhamdullilah, has 236 friends. He claims to operate from a mosque in Vienna’s Donaustadt but according to the Kurier no such mosque exists.
Images on the Facebook group page show individuals posing with the IS flag and in ‘battle dress’ in Floridsdorf and various other locations in Vienna.
Some of the fans appear to originally come from Afghanistan, Chechnya, and Macedonia. One fan, who identifies himself as a Turkish migrant in Vienna, writes: "I have deleted all the false friends in my life and am happy about that. I want to find, inshallah, some true friends..."
Austria’s State Office for the Protection of the Constitution is powerless to do anything about such groups. It is not forbidden to parade a jihadist flag through Vienna or to sell caps with terrorist symbols on them.
However, membership of a terrorist organisation is prosecutable under Section 278, and if known jihadists return to Austria after fighting in Syria, they will be interrogated.
Islamic State has become one of the main jihadist groups fighting government forces in Syria and Iraq.
Its precise size is unclear but it is thought to include thousands of fighters, including many foreign jihadists.