Monopoles are essentially a theoretical particle, an isolated magnet with only one magnetic pole. This would mean that the particle would have a net magnetic charge. What would that mean in simple terms? The notion that the magnetic field has zero divergence would be proven wrong; in fact, magnetic particles would most likely behave even more similarly to electric particles, in that not only would magnetic particles have two opposing charges, but, in the same manner negatively and positively charged particles exist, north and south pole magnetic particles would also exist; the "south pole magnets" and "north pole magnets" would not have to cancel out, a rule already accepted in physics today.
What do you guys think? What would the discovery of a monopole (if one exists) mean for what we already understand about electromagnetism?