Hello World in 1024 characters
C# (and without “Hello World” anywhere)

Code-golfed, so that obviously no unnecessary whitespace is used:

using System;using System.IO.Compression;using System.Runtime.Serialization;using System.Runtime.Serialization.Json;using System.Linq;using System.Net;using System.Text.RegularExpressions;class C{static void Main(){var g=WebRequest.Create("https://api.stackexchange.com/2.1/questions/8859?site=codegolf&amp;filter=withbody");var r=(HttpWebResponse)g.GetResponse();if(r.StatusCode==HttpStatusCode.OK){var s=r.GetResponseStream();foreach(var a in r.ContentEncoding.ToLowerInvariant().Split(',').Reverse())switch(a){case"gzip":s=new GZipStream(s,CompressionMode.Decompress);break;case"deflate":s=new DeflateStream(s,CompressionMode.Decompress);break;default:throw new InvalidOperationException();}var d=new DataContractJsonSerializer(typeof(R));var q=(R)d.ReadObject(s);var e=new Regex("&lt;code&gt;([^&lt;]*)&lt;/code&gt;");var m=e.Match(q.I[0].B);Console.WriteLine(m.Groups[1].Value);}}}[DataContract]public class R{[DataMember(Name="items")]public I[]I{get;set;}}[DataContract]public class I{[DataMember(Name="body")]public string B{get;set;}}


Formatted for readability:

using System;
using System.IO.Compression;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.Linq;
using System.Net;
using System.Text.RegularExpressions;

class C
{
    static void Main()
    {
        var g = WebRequest.Create("https://api.stackexchange.com/2.1/questions/8859?site=codegolf&amp;filter=withbody");
        var r = (HttpWebResponse)g.GetResponse();
        if (r.StatusCode == HttpStatusCode.OK)
        {
            var s=r.GetResponseStream();
            foreach (var a in r.ContentEncoding.ToLowerInvariant().Split(',').Reverse())
            switch(a)
            {
                case "gzip":
                    s = new GZipStream(s,CompressionMode.Decompress);
                    break;
                case "deflate":
                    s = new DeflateStream(s,CompressionMode.Decompress);
                    break;
                default:
                    throw new InvalidOperationException();
            }
            var d = new DataContractJsonSerializer(typeof(R));
            var q = (R)d.ReadObject(s);
            var e = new Regex("&lt;code&gt;([^&lt;]*)&lt;/code&gt;");
            var m = e.Match(q.I[0].B);
            Console.WriteLine(m.Groups[1].Value);
        }
    }
}

[DataContract]
public class R
{
    [DataMember(Name="items")]
    public I[] I { get; set; }
}

[DataContract]
public class I
{
    [DataMember(Name="body")]
    public string B { get; set; }
}


The program retrieves this question from Code Golf using Stack Exchange API, finds the first piece of text formatted as code (which, in case of this question, is the “Hello World” text), and prints it out.