What do you mean "starring/flagging items for later"? 1. To read an article later as you have no time now. 2. To save a read article for later reference.

I use google reader, so:

For 1. I just keep items unread (key 'm'). This means I keep all my 'unread' and 'read-for-later' items in the same list in the same view in the reader.

For 2. I do not flag/star anything for reference as I trust Google Reader's search options to find stuff in the feeds. Google will find things way more easily than any scheme I think of to keep stuff referenced.

For your question: Why use 'star' or 'flag' at all as they have inherent semantic meaning depending on the person.

Why not leverage that to its fullest and just say 'marked/unmarked' and leave it up to the user to define what it means.