SF's right, give it some time and you'll probably start seeing some interesting things. My tank has been up and running for under three months, so it's just a wee baby. The rock was BARE when I bought it, with the exception of some corraline. Within weeks, many colours of corraline appeared, but I didn't get any of the larger hitchhikers I've read about like crabs, pistol/mantis shrimp, big sponges, polyps etc. At first I was disappointed (I'd hoped for something exciting like a free pistol shrimp), but I'm actually happy that any larger life in my tank is there by my choice - who wants a mantis anyway?!
Here are some of the little critters that have 'appeared' out of the LR:
Copepods, amphipods and isopods (the harmless kind)
Tunicates
Sponges - two types, forget the names ATM, one looks like little Q-Tips, the other looks like a volcano in shape. There may also be an 'encrusting' sponge, not sure if that's what it is
Tiny starfish - Asterina (sp?) and brittle stars
Spaghetti worms
Bristleworms
Tiny snails - two different types
One clear flatworm
2mm round creatures that floated in open water and stuck to glass, possibly tiny jellyfish (gone now)
Several explosions of 1mm creatures that swim in open water, possibly shrimp larvae - fish love 'em!
A ~1/8" limpet
Two little Aiptasia anemones, which I've killed with Kalk paste (not everything that pops out of LR is desirable in a reef tank)
Feather dusters galore - more pop up every week, there are several different kinds from the looks of it
Take a look at your tank during the night - see if you can get a red lens for your flashlight, since fish and critters don't seem to be disturbed by red light. I see more tiny life at night than by day, it's fascinating watching everything that's living in/on/around the rock.