if you have a decent size tank I would get a plecostomus fish at your local fish shop. It worked out great for me and cleaned up my algae problem within two days. Pleco does a better job than any snail out there IMO.
I highly advise against getting a fish to solve a problem. Get a fish because you want it not because you need it. It is best to find the cause of the algae and fix that.
Also, what type of substrate do you have? Pictures would also be helpful.
Isn't it true that most tanks have algae eaters in it? Yes you are correct in saying that this person must find the source to the algae problem but a pleco or any algae eater is a great solution after the problem is found. Majority of fish owners have some type of algae eater in their tank because algae can be a nuisance.