News of the flotilla raid in Gaza has sparked an uprising in Egypt. Thousands of Egyptians protested both Israel's actions and the stance of their own government earlier this week. President Mubarak's recent decision to open up the previously blocked Rafa terminal into Gaza on June 1st, has been a stark departure from recent policy, and the Egyptian blogosphere has been ablaze with responses.

Jon Jensen at the Global Post describes the Egyptian reaction:

Earlier this week, downtown Cairo was also rocked by several protests against the blockade of Gaza. The demonstrations saw more than 1,000 Egyptians hurling insults at Mubarak and his government.
Egypt’s Foreign Ministry called the flotilla killings “tragic,” criticizing the “unjust Israeli siege on the Gaza Strip.” But even as the Foreign Ministry’s press statement was released, Egyptian opposition groups had rallied outside the building, denouncing Egypt’s complicity in the blockade while screaming “Down with Mubarak.”
“Until this week, the Egyptian government had been trying to downplay their role in the blockade, especially in the Arab world,” said Diaa Rashwan, an expert at the Al-Ahram Center for Political and Strategic Studies, a government-funded think tank. But after the Israeli flotilla affair, now I think there is a real change in the Egyptian strategy.”

Rafah’s border crossing, normally a sleepy, desolate stretch of sand, has been bustling with activity both inside and out, with eager travelers filling the terminal’s arrival and departure halls, and trucks laden with aid supplies lining up for entry into Gaza.
Still, several Gazans coming into Egypt claimed that there were still thousands of sick Palestinians on the other side waiting to cross; one estimate was as high as 8,000.

Eileen White Read at Palestine Note writes:

Thus it was a wise move by the Egyptian government this morning to defuse the time bomb of Palestinian anger by opening the Rafah gate – the only gate it controls – to allow some of Gaza's 1 1/2 million civilians to escape their collective punishment for the actions of the ruling Hamas party. Though Egypt hasn't said how long it will keep the Rafah border open, its opening is the escape valve that could help prevent another intifada. — Palestine Note

Hossam el-Hamalawy, from Arabawy.org, described street protests in the NYTime's Room For Debate:

Tens of thousands of peasant conscripts, dressed in the black uniforms of Egypt’s notorious Central Security Forces, were mobilized in the main squares, university campuses and central mosques, as demonstrators vented their anger not only on Israel’s actions but also on the ailing 82-year-old Hosni Mubarak’s role in aiding Israel in that siege.
The demonstrators chanted beautifully rhymed, yet angry, slogans against Israel and the U.S., but quickly the chants changed to denouncements of the police presence, torture, electoral vote-rigging, privatization of state-owned firms and the deterioration in the country’s national insurance system. In what has become a ritual, young activists broke the security cordon laid around the protest site, drawing parallels between the siege of Gaza and the siege the protesters were feeling among the overwhelming police presence.
Israel’s recent actions in the sea amount to nothing but piracy and state-sponsored terrorism. If the U.S. has an ounce worth of respect for human rights, it should be the first to call for prosecuting the Israeli perpetrators of those killings. The international community also has to come to terms with the fact that there is an elected government in Gaza, which yes happens to be Islamist and involved in resistance attacks against an occupying power.
Military and financial aid to Israel, President Mubarak and the rest of the Arab dictators who are ruling their nations with draconian security services, torture chambers and failed economic policies, must cease immediately. The Egyptian people, just like the Palestinians, feel like they are under occupation.

From the MEMRI blog:

The deputy secretary-general of the Muslim Brotherhood bloc in the Egyptian parliament, Muhammad Al-Baltaji, who heads the Arab delegation to the Gaza aid flotilla, wrote in an article that the ships were purchased to facilitate future flotillas of this sort, since the activists were adamant not just to extend humanitarian aid but also to break the Gaza siege.
He stated that the flotilla organizers had declined Egypt's invitation to reach Gaza through its territory, and had opted to reach it by sea despite the difficulties, knowing that an attack by Israeli forces would only gain the attention of the international community.

Issandr El Amrani at the Arabist discusses the effects this will have on potential political changes in Egypt:

Even in Cairo, where pro-Palestinian demos have been very, very tightly restricted since the Gaza war — since the regime doesn't want any reminders of its role in the Gaza blockade — today was a surprise. At first, the protest outside the Ministry of Foreign Affairs seemed disappointed, with only a few dozen participants. But this evening, thousands gathered at the al-Fath mosque on Ramses Square and staged an impressive protest, even if they were penned in by several hundred uniformed riot control troops and police officers, as well as tons of plainclothes security people and a bunch of baltiguiya (street toughs hired to intimidate, and need be, beat up protesters).
It's important to note that this is the biggest protest about Palestine since the Gaza war, in an atmosphere in which such protests have not been tolerated. We might see more in the next few days, including on Friday after prayers. This may revive local activism on Gaza as well as linkages made between the situation there and the situation in Egypt — notably the Mubarak regime's collaboration with Israel on the blockade. Expect a fierce fight in the media over this in the next few days, and more opportunities to express all sorts of grievances. But when Turkey expels its ambassador and Egypt is seen to be doing nothing, it looks very, very bad for Cairo.

Zeinobia at Egyptian Chronicles speculates on the link between the flotilla crisis and Egypt's political future:

What is the relation between what happened on the Gaza Flotilla and democracy in Egypt !!?? Some may not see relation while others know that due to the lack of democracy in Egypt the Egyptian regime had to close the crossings and to become an accomplice in a blockade that the UN itself denounces. It has become a usual thing to read that “if Egypt had not closed the crossing , the flotilla massacre would not have happened”
Only yesterday Mubarak due to the international pressure and embarrassment has ordered the opening of the crossing for unlimited use.

From Egypt Daily Digest, posted by @mfatta7, here is a video of Alexandria street protests:

Here are further reactions from Twitter:

@amirahoweidy: http://goo.gl/6xi1 video of massive demo in alex egypt chants: “down, down with israel!” via @mfatta7 #flotilla #gaza

@fuwaka_mejnoon: Why won't #Hamas let the #flotilla aid in? That's like saying it's not urgent or admitting that tunnels from #Egypt are adequate short term.

@_Enimey_: with now turkey has appeared on the surface Egypt now can rest / why? // Israel had Egypt as a ring in it's finger cuz of the Nile #flotilla