I was pulled up sharp by this report about an XBox user whose account was suspended because he used "offensive language" in his details, the offence being that he lived in a city in the USA called Fort Gay.
I'm continually astonished by the stilted sensibilities of some Anglo-Saxon communities (I have never come across policies banning "offensive language" in systems for any other language) - like most of my fellow Europeans I can't imagine why the word "gay" should be deemed offensive. But this incident highlights the problematic use of obscenity lists which cause problems all the time for large numbers of innocent Internet users.
Gay, for example, is a common given and family name in the English-speaking world, and there are many streets and places named after those people. There are many people with the surnames Duck or Mouse, and some are called Donald or Michael; and they have a constant battle to achieve anything online. The good burgers of Scunthorpe in England have a very trying time with web sites and spam filters (think about it); and imagine the issues that the inhabitants of Dildo in Newfoundland, Condom in France and Fucking in Austria have.
If you do feel the need to check for obscenities, it needs to be done in a more knowledgeable, culturally-aware way than is currently the case.