No guesspert, but either someone has searched it in the past on that computer, it get billions of hits from many people out there, the easy way maybe to get rid of that is to go to internet options...
It's not www.maplestory.com, it's maplestory.nexon.net. Problem solved.WRONG! this is because you used the meso generator. delete it!! and then google the answer to do what you need to do because...
You probably have a virus. Get a good blocker, there are free programs on the Internet, do a search under porn blockers. There are many to choose from.