Why does the toilet keep getting clogged?

Usually it's either a problem with the sewage system itself - narrow pipes, bends where stuff accumulates, or the toilet itself is to blame - the flush system might be clogged or there's a blockage right in the siphon. I saw a similar situation at my neighbors' place - turned out they were throwing everything down there instead of actually using a trash can. Try plunging it first or using a plunger, and if that doesn't help - call a plumber to check out the pipes.