Cute Little Snails

All of a sudden I've noticed perhaps hundreds of tiny snails climbing on the exterior of my house. Maybe they come around every year and have escaped my attention. I've lived in this house for more than nine years and this is the first time they've popped out at me. I don't mean that they literally "pop out at me". They just scoot along, sometimes leaving a gross slime trail, up the walls and back down, and occasionally sideways. But never diagonally. What are they doing? What do they want? Does their sudden ubiquity have to do with our recent storms? I just don't know. I think I should look up information about snail behavior so I'll have greater insight into why they do what they do. That's all for now.