They still singing that? I was under the impression it has been deemed racist and the Jewish Community has asked them not to use the word.
At a City v Spuds match in the 90's I was sat in the Main Stand at Maine Road and a pissed up City "fan" stood up and shouted "fuck off back to Belsen" There were a lot of our fans who turned on him and he was removed from the ground by the Police (one of them was a mate of mine). I got talking to the guy who sat in front of me with his daughter (she played Elsa in Emmerdale) and he told me he was Jewish and City had a significant support amongst the Jewish community and the abusive fan had disrespected their religion with reference to the Holocaust.
In this day and age we all have to be aware of the Society we live in and have respect for other cultures, "Yid" appears to be a grey area but one which I don't think should be used.