+``added``
+ Match all messages containing "added", but also those containing "add", "additional",
+ "Additional", "adds", etc... via stemming.
+
+``(and Bob Marley)``
+ Match messages containing words "Bob" and "Marley", or their stems
+ The words need not be adjacent.
+
+``(not Bob Marley)``
+ Match messages containing neither "Bob" nor "Marley", nor their stems,
+