Here's the code for my last post on Annotations - I tidied up a few things up (it's still very basic but it does work) there's a single test fixture to give you a guide for usage... so things like:

[Test]
public void QueryStoreForClassAnnotationsWithCertainKey()
{
    ClassA target1 = new ClassA();
    ClassA target2 = new ClassA();
    ClassA target3 = new ClassA();

    target1.Annotate(Description => "class number 1");
    target2.Annotate(Description => "class number 2");
    target3.Annotate(Parsed => true);

    var results = AnnotationStore.Classes
      .Where(a => a.HasKey("Description"))
      .ToList();

    Assert.AreEqual(2, results.Count);
}

And also the equivalent thing is possible for members... though I suspect annotating members isn't all that useful in most cases...

[Test]
public void QueryStoreForMemberAnnotations()
{
    ClassA target1 = new ClassA();
    ClassA target2 = new ClassA();
    ClassA target3 = new ClassA();

    target1.Annotate(() => target1.FirstName, CamelCase => true); // annotating a property
    target1.Annotate(() => target1.Field, Ignored => true); // annotating a field
    target2.Annotate(() => target2.Execute(), Parsed => true); // annotating a method

    target3.Annotate(Parsed => true);

    var results = AnnotationStore.Members
      .Where(p => p.HasKey("CamelCase"))
      .ToList();

    Assert.AreEqual(1, results.Count);
}