What do the arrows on this Feynman diagram represent? The picture follows the convention of the time axis being on the vertical direction. 
I think this Feynman diagram represents Coulomb repulsion between two electrons with a virtual photon being absorbed and emitted by each electron. 
What are the arrows on the electron lines for? I'm not sure what information this tells us. 

 A: They tell you whether they're electrons or antielectrons (positrons). The convention is that if the arrow points the same direction that time flows then it's an electron, and if it points the opposite direction then it's a positron. In this case the arrows point in opposite directions so one particle's an electron and the other's a positron and the process represents an attraction, although knowing which is which requires specifying whether time flows upward or downward.
A: The arrows represent particle flow (or some people say, "flow of charge"). An arrow with time is a particle and an arrow against time is an anti-particle. Note that the e's do not have a plus or minus. That is the correct way to write a Feynman diagram. You infer which ones are electrons and which are positrons from the direction of the arrow. This allows you to rotate the diagram around and interpret the same diagram as different processes.
So in this case, with time flowing upward vertically, this is a positron (left) interacting with an electron (right). In other words, coulomb attraction.
If time is flowing left to right, then it's an electron (top) annihilating with a positron (bottom), followed by electron-positron creation
See here for a nice description.
