I have a yellow mystery snail. He/she seems to love skirting along my live plants, but does not seem to do any damage to them... I read they eat the dead/decaying plant parts so help to clean things up a bit. But, I don't think that little snail (although, a big snail, but comparatively speaking) will do much cleanup in a large tank with lots of plants.
Dragon, my oldest tank is a few yrs... well... not true... I had it shut down for awhile. But the gravel stayed wet..... I don't know. I guess my oldest tank is no more than 5-6 months old.
edit: Oh, and I did look at that website before but could not find an exact match. I posted pics of my oddball algae on this thread before. i will show you.
Celie the spoiled 8 yr old Chihuahua
Arwin the naughty Papillon puppy
No fishies for me right now... expecting a baby in June 2013!