diff -r 4d0d4e12c1ec -r 8503a20726d2 data/dictionary.xml
--- a/data/dictionary.xml	Mon Aug 12 22:04:45 2013 +0200
+++ b/data/dictionary.xml	Mon Aug 12 22:40:38 2013 +0200
@@ -257,7 +257,41 @@
 	</concept>
 	<concept>
 		<term abbreviation="MDA" completeForm="message delivery agent " language="en"/>
-		<explanation language="en"><text></text></explanation>
+		<term abbreviation="LDA" completeForm="local delivery agent" language="en"/>
+		<explanation language="en">
+			<text>
+				a software component that receives e-mail from the MTA and stores them in the recipient's mailbox;
+				the MDA can also apply Sieve filters on processed messages;
+				examples of MDA: Dovecot, Cyrus IMAP, procmail, maildrop
+			</text>
+		</explanation>
+		<tag>computer</tag>
+		<tag>messaging</tag>
+	</concept>
+	<concept>
+		<term abbreviation="" completeForm="sieve" language="en"/>
+		<explanation language="en">
+			<text>
+				a standardized language for describing e-mail filters;
+				the MDA can apply system-wide or user-defined filters on incoming messages;
+				a filter has conditions (connected logical operators: AND, OR…) like „message header contains value X“
+				and actions that will be done with the message like „file into folder X“ or „add flag/label 1“ or „redirect message to some.address@example.com“ or „discard message“;
+				filters are executed on the server where MDA resides,
+				so they are independent on the MUA currently used by the user
+				and works even if the user is offline (useful for OOTO messages when the user is on vacation)
+			</text>
+		</explanation>
+		<tag>computer</tag>
+		<tag>messaging</tag>
+	</concept>
+	<concept>
+		<term abbreviation="OOTO" completeForm="out of the office" language="en"/>
+		<explanation language="en">
+			<text>
+				an automatic response on a message (e-mail, SMS etc.) which is sent when user is for example on vacation and can't respond immediately;
+				in case of e-mail it can be easily configured as a Sieve filter
+			</text>
+		</explanation>
 		<tag>computer</tag>
 		<tag>messaging</tag>
 	</concept>
@@ -1972,12 +2006,6 @@
 		<explanation language="en"><text></text></explanation>
 	</concept>
 	<concept>
-		<term abbreviation="OOTO" completeForm="out of the office" language="en"/>
-		<explanation language="en"><text></text></explanation>
-		<tag>computer</tag>
-		<tag>messaging</tag>
-	</concept>
-	<concept>
 		<term abbreviation="" completeForm="streamlining" language="en"/>
 		<explanation language="en"><text>delivering better product faster with smaller teams of less-experienced engineers</text></explanation>
 		<!-- Internal: if you dont understand, just ignore it :-) -->