How the Heartbleed Bug Works:

[[Meg stands by a server. There's a thought bubble arising from the server showing the data the server is currently processing, including a portion that states "User Meg wants these six letters: POTATO."]]
Meg: Server, are you still there? If so, reply "POTATO" (6 letters).

[[The 6 letters "POTATO" are highlighted yellow in the server's thought bubble, and the server emits "POTATO".]]

[[The phrase "User Meg wants these 4 letters: BIRD." is in the server's thought bubble with other data around it, with "BIRD" highlighted. The server is emitting "BIRD".]]
Meg: Hmm...

[[The phrase "User meg wants these 500 letters: HAT." is in the server's thought bubble, along with other data around it.]]
Meg: Server, are you still there? IF so, reply "HAT" (500 letters).

[["HAT" and many more characters after it in the thought bubble are highlighted, and the server emits a long string of text starting with "HAT" but then including much more other unrelated data. Meg is busily writing it down in a notebook.]]

{{Title text: Are you still there, server? It's me, Margaret.}}