why empty list is better than null

contrived.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var data = DataFetcher.GetData();
            var stringsForUser = DataExplainer.BuildStrings(data);
            // TODO: handle stringsForUser being null since we don't have non-null reference types in C#

            // THIS IS WHERE WE ARE SENDING OUTPUT TO THE USER, AND WHERE WE SHOULD THEREFORE HANDLE THE CASE OF EMPTY
            if (stringsForUser.Any() == false)
            {
                Console.WriteLine("No data was found");
            }

            foreach (var stringForUser in stringsForUser)
            {
                Console.WriteLine(stringForUser);
            }
        }
    }

    public static class DataFetcher
    {
        public static List<int> GetData()
        {
            // 50/50 chance you'll actually get data back
            if (new Random().Next()%2 == 0)
            {
                return new List<int>() { 1, 2, 3 };
            }
            else
            {
                return new List<int>();
            }
        }
    }

    public static class DataMunger
    {
        public static List<int> Square(List<int> input)
        {
            // TODO: handle input being null since we don't have non-null reference types in C#
            return input.Select(x => x*x).ToList();
        }
    }

    public static class DataExplainer
    {
        public static string GetExplanation(int original, int squared)
        {
            return String.Format("The square of {0} is {1}", original, squared);
        }

        public static List<string> BuildStrings(List<int> input)
        {
            // TODO: handle input being null since we don't have non-null reference types in C#
            var squared = DataMunger.Square(input);
            var explanations = input.Zip(squared, GetExplanation).ToList();
            return explanations;
        }
    }
}