diff --git a/metropolis/pkg/event/etcd/etcd.go b/metropolis/pkg/event/etcd/etcd.go
index 041e600..ff40bcd 100644
--- a/metropolis/pkg/event/etcd/etcd.go
+++ b/metropolis/pkg/event/etcd/etcd.go
@@ -14,11 +14,11 @@
 )
 
 var (
-	// Type assert that *Value implements event.Value. We do this artificially,
-	// as there currently is no code path that needs this to be strictly true.
-	// However, users of this library might want to rely on the Value type
-	// instead of particular Value implementations.
-	_ event.Value = &Value{}
+	// Type assert that *Value implements event.ValueWatcher. We do this
+	// artificially, as there currently is no code path that needs this to be
+	// strictly true.  However, users of this library might want to rely on the
+	// Value type instead of particular Value implementations.
+	_ event.ValueWatch = &Value{}
 )
 
 // Value is an 'Event Value' backed in an etcd cluster, accessed over an
@@ -54,11 +54,6 @@
 	return data, nil
 }
 
-func (e *Value) Set(val interface{}) {
-	// TODO(q3k): split up the Value interface into ValueReader/ValueWriter
-	panic("Set is unimplemented on etcd values")
-}
-
 func (e *Value) Watch() event.Watcher {
 	ctx, ctxC := context.WithCancel(context.Background())
 	return &watcher{
diff --git a/metropolis/pkg/event/event.go b/metropolis/pkg/event/event.go
index d3ea5df..6c40666 100644
--- a/metropolis/pkg/event/event.go
+++ b/metropolis/pkg/event/event.go
@@ -105,6 +105,16 @@
 	// this should be negotiated and serialized externally by the producers.
 	Set(val interface{})
 
+	// ValueWatch implements the Watch method. It is split out into another
+	// interface to allow some 'Event Values' to implement only the watch/read
+	// part, with the write side being implicit or defined by a more complex
+	// interface then a simple Set().
+	ValueWatch
+}
+
+// ValueWatch is the read side of an 'Event Value', witch can by retrieved by
+// Consumers by performing a Watch operation on it.
+type ValueWatch interface {
 	// Watch retrieves a Watcher that keeps track on the version of the data
 	// contained within the Value that was last seen by a consumer. Once a
 	// Watcher is retrieved, it can be used to then get the actual data stored