I've heard that they are Nocturnal Slime Suckers, which might be a good name for a new rock band.
You can discourage algae growth by decreasing light, by adding live plants to eat the algae food, by making sure that all the fish food gets eaten, and by removing waste products. Any supplements that encourage plant growth will also encourage algae growth, so if you're using them you could cut back a little. Some people feel that a bit of algae is just a natural part of an aquarium. Algae spores are airborne and will grow in most any water. If the driftwood algae really bothers you and conservative methods don't work, you could always remove the driftwood and scrape off the algae with a stiff brush or something. Total darkness will also kill algae infestations, not to mention live plants.