A crescent embracing the cross set in white against a black background. This has been the most prevalent Facebook picture chosen by thousands of Egyptian users to express their grief and anger at the New Year's Eve bombing of Two Saints Church. Portraits of Jesus Christ also abound, many on the Facebook pages of Muslim, and not just Christian users. Another prominent profile picutre has the words "In mouring for Egypt's martyrs", also set against a black background.

Active Facebook users in Egypt have been rallying in denunciation of the bombing of Two Saints Church in Alexandria, and in solidarity with Egypt's Copts.

The social network has been increasingly used by growing numbers of its four million Egyptian users as an instrument of mobilization and awareness raising around political and social issues. Most recently, tens of thousands of users set up a Facegroup supporting former International Atomic Energy Agency director Mohamed El Baradei as a presidential candidate in the forthcoming presidential elections scheduelled for automn this year.

But, says Rasha Abdallah, the head of the American Univeristy in Cairo's (AUC) mass communications department, the outpourings of anger, grief and solidarity sentiments expressed by Facebook users over the past few days is virtually unprecedented.  “People came together in a way I have not seen before,” she said.

On their status lines, many Copts wrote: “Egypt, I am angry - a Coptic Egyptian.” Others, both Muslim and Christian: “Terrorism has no religion.” Many Muslim users used their status lines to send messages of condolence to the victims' families and to the Coptic community at large.

The most encouraging aspect of this outpouring of solidarity sentiments on Facebook in the aftermath of the church bombing is the “recognition that we have a problem and we need to work on it, on the contrary to the government’s stand,” says the AUC's Abdullah.

Among the foremost initiatives promoted by a great many Facebook users has been the call on Egyptian Muslims to make of themselves "human shields" to Copts, by attending Coptic Christmas Eve mass on 6 January. How far this and other political and social initiatives are able to transcend the virtual boundaries of digital networks and make a real impact on the ground remains to be seen.

However, as Abdallah puts it, “it is enough that Facebook users initiate the idea, then it should be taken from there to the mainstream media thus reaching a wider audience.”

For her own part, Abdallah created a Facebook group on the day following the bombings demanding that the "religion" entery in the national ID card be removed. It's mere presence, according to Abdallah, "is a message from the government that religious identity matters."