Nobody has ever needed to do this before

So I'm still trawling through this ASP.NET app and keep finding great WTFs. I spotted this method in one of the classes

private ArrayList SplitString(string str, string separator)

So presumably the writer of this piece of code assumed nobody had ever faced a similar problem before and might have provided a solution in the framework???? Anyway, that's some more redundancy I can get rid of.