Maybe you don't speak Arabic, in which case this ad might not mean much. But to the people of Egypt, it's a strong warning against trusting outsiders.
Here's the gist of what the ad alleges: foreigners are invading Egypt as spies. While they may seem friendly, they're in your country to gather intel, so it's best to keep your mouth shut.
The AP article offers a translation and description. The ad starts with the foreigner arriving in an Egyptian cafe and scanning the room.
"From the beginning, he knows why he is here and sets up his goal. He won't have to spend much time getting to know the people in the place." The foreigner then spots three young Egyptians and heads over to them, saying in broken Arabic: "I love you so much." The narrator says: "Our generosity has no limits," as one of the Egyptians stands up, shakes hands and invites the foreigner to sit with them.
The ad closes with, "Every word comes with a price. A word can save a nation."
According to participants of Egypt's uprisings last year, the ads are actually a tactic to keep Egyptian people from speaking with foreign journalists. The ads also subtly suggest that revolutionaries are spreading "dangerous information" designed to undermine the Egyptian government.
What isn't clear is where this ad — and one other like it — originated. It could be the product of Egypt's security agencies, which are still up and running despite Hosni Mubarak's removal from power. These agencies have long targeted foreigners, and have been particularly wary in response to the country's uprisings.