Cairo is not a very safe destination for any tourists right now. There is a lot of terrorist activity in the area, and while it is not directed specifically at Americans, it does not make for an ideal vacation destination.
Traveling to Egypt and Cairo is safe for Americans, however if you are a women I highly suggest you read up on the customs and travel with a group of people. Getting around Cairo is difficult so if you plan to go for fun go with a tour group.
In Fort Lauderdale, the whole city became Egypt. And now, all of a sudden, we have a flood of American tourists! They have found out that Egypt is safe.