Observer Pattern Code Review

class Subject { public delegate void Callback(Blogs blog);
Dictionary<String, Callback> notify = new Dictionary<String, Callback>(); Simulator simulator = new Simulator();
const Int32 speed = 4000;
private void Register(String blogger) { if (!this.notify.ContainsKey(blogger)) { this.notify[blogger] = delegate { }; } } private void Run() { foreach (Blogs blog in simulator) { this.Register(blog.Name); this.notify[blog.Name](blog); Thread.Sleep(speed); } } public void Attach(String blogger, Callback update) { this.Register(blogger); notify[blogger] += update; } public void Detach(String blogger, Callback update) { notify[blogger] -= update; } public void Go() { new Thread(new ThreadStart(this.Run)).Start(); } }

class Blogs { public String Name { get; set; } public String Topic { get; set; }
public Blogs(String name, String topic) { this.Name = name; this.Topic = topic; } }

class Simulator : IEnumerable { Blogs[] bloggers = { new Blogs("Jim", "UML diagrams"), new Blogs("Eric", "Iterators"), new Blogs("Eric", "Extension Methods"), new Blogs("Judith", "Delegates"), new Blogs("Eric", "Type interface"), new Blogs("Jim", "Threads"), new Blogs("Eric", "Lamda expressions"), new Blogs("Judith", "Anonymous properties"), new Blogs("Eric", "Generic delegates"), new Blogs("Jim", "Efficiency") };
IEnumerator IEnumerable.GetEnumerator() { foreach (Blogs blog in bloggers) { yield return blog; } } }