twerppoet said:I'm not completely sure what you mean by tag items, but;
Reeder will let you mark items as favorite, and that favoritism will sync back to Google Reader.
Other options in the app include the ability to send the article to Instapaper or Readability for later perusal, email the link or article, post the link to FaceBook, and a few other options I haven't explored.
emm said:River of News lets you star items to save them.