Sometimes we read title of an item in Google Reader and may want to read that item in full at a later time. In such case (just like in email), we can mark specific item as ‘unread’ and it will be highlighted for future reading. This is very useful feature to create list of ‘unread’ items that can be read at future ‘leisure’ time.
Marking Google Reader items as ‘unread’
1. Login into your Google Reader account at google.com/reader
2. Click to expand specific item in the reader.
3. Then click to check ‘Keep unread’ option at the bottom of expanded item.
‘Unread’ does not work, use ‘Add Star’ feature
Google Reader calculate unread counts for items less than 30 days old or the last 10,000 items, whichever comes first. Hence, unread items older than 30 days or last 10,000 items will not show up as unread (even though you marked them ‘unread’ previously). [source]
So besides using ‘unread’ feature, you can use ‘add star’ feature to mark and highlight items in order to create (permanent) list of item meant to be read at later time.