minor revision

Author: Andrew Leung

draft/tutorial/expire-least-recently-used-data.txt

@@ -7,8 +7,8 @@ Expire Least Recently Used Data from a Collection
 .. versionadded:: 2.2
 
 Least recently used, or LRU, data retention patterns are used in simple
-data caches or support for stateless systems. They are convenient for a
-number of situtions where simple TTL collections are not enough.
+data caches or support for stateless systems. By extending TTL
+collections with application support provides additional features.
 
 This pattern presents some cases and proides a pattern for maintaining
 documents in MongoDB where LRU documents are retained while others are
@@ -43,13 +43,11 @@ Use Case
 - Transcoded media cache
 
   Archival images and videos are stored in a high quality format and
-  transcoded to device specific formats for distribution. Caching
-  frequently accessed media improve overall performance and save on
-  computing power without creating overly complex 
-
-  setting up a list to keep track of where various transcoded versions
-  exist 
-
+  transcoded to device specific formats for distribution. Keeping
+  lists of frequently accessed media in cache and transcoding archive
+  materials on demand can provide excellent application response while
+  maximizing resources.
+  
 Solution
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