The world media covering the Egypt turmoil has been largely referring to the protesters as "opposition groups," but this general name represents several groups that often have varied and conflicting agendas. 

Here is a short background on the key opposition groups in Egypt:

The Muslim Brotherhood

The Muslim Brotherhood is the most prominent opposition group in Egypt. Though it seems they were not the ones to organize the wave of protests, they have definitely exploited them to voice their agenda: to form a state governed by Islamic law.

This Sunni movement was founded in 1928, partly in response to the British occupation in Egypt, and became one of the first and most successful movements advocating Islam as a political program. Over the years the group gathered many supporters and established branches throughout the world. (Gaza-ruling Hamas party originated in the Palestinian branch of the Muslim Brotherhood.)

Though there was never proof of the group's involvement in terror acts, its motto is: “Allah is our objective; the Koran is our constitution, the Prophet is our leader; Jihad is our way; and death for the sake of Allah is the highest of our aspirations.”

The movement has been banned in Egypt since 1954 after being accused in the assassination attempt of President Gamal Abdel Nasser (a charge the Brotherhood has always denied). Still, the Brotherhood operates openly within limits that vary at the whim of the authorities.

Until last year, members of the movement running as independent candidates held one-fifth of the seats in parliament, but after loosing many seats in the 2010 elections, which were marred by serious fraud, the group boycotted the second round of elections and announced it would shift its political struggle to the streets.

The Brotherhood has huge influence on the Egyptian public and group emerging as the ruling party is perceived as a very possible scenario. Some fear the group could threaten U.S. interests on issues including Arab-Israeli peace efforts if they gain power.

ElBaradei and the National Association for Change (NAC)

The National Association for Change is an umbrellas organization of the Egyptian opposition groups of all political affiliations and religion. The goal of the group is to bring about political reform based on democracy and social justice. This organization was set up by Nobel Peace Prize laureate Mohamed ElBaradei, former head of the IAEA, who returned to Egypt on Jan. 27 to lead the protests.

ElBaradei has been calling for democratic reforms in Egypt for quite some time and keeps declaring his wish not to rule Egypt but to be a "tool for reform" – or, in other words, lead the transition government when or if Mubarak resigns.

However, the NAC includes parties like the religious Muslim Brotherhood on one hand, and Liberal political parties like Al-Ghad on the other. And the group is having a hard time agreeing on a cohesive strategy.

Although ElBaradei currently enjoys the support of the majority of the opposition groups in Egypt, including the Muslim Brotherhood, and while even the U.S. government sees him as a possible leader of an interim government, it is hard to tell if he could get elected beyond that. 

6 April Youth movement

This is a left-wing socialist Facebook group -- or at least it started on Facebook -- and moved to the real world. They were the main organizing force behind the original demonstration on Jan. 25.

The group was established in 2008 in support of a workers' strike in an industrial Egyptian town, but continued its activities well past that strike. The group's Facebook page today includes almost 90,000 supporters, predominantly young and educated members, most of whom had not been politically active before.

Ahmed Maher, one of the founders of the group, was arrested by the Egyptian authorities several times in the past years. The group's main ideology is free speech and anti-nepotism.

WAFD party

The WAFD party is a nationalist liberal party in Egypt. It is the extension of one of the oldest and historically most active political parties in Egypt. It supports political, economic and social reforms, promoting democracy, ensuring basic freedoms and human rights and maintaining national unity. It has led the official opposition in parliament, but it chose to boycott the 2010 elections because of widespread voting fraud.

AL GHAD Party

This is another active political party established in 2004. It is a centrist liberal secular party.

Its founder, Ayman Nour, was imprisoned by the Mubarak government for three years after the 2005 elections, in which he garnered 7 percent of the vote, coming in second to Mubarak. His imprisonment got harsh criticism in Egypt and by European and American leaders.

Nour has been taking part in the demonstrations that started last week, but he does not seem to enjoy the same high profile he had in the past.