Who cares? You can't put every genie back into the bottle- measure your words, thoughts, and opinions and this won't be a problem. And reviews can change over time (a sports team goes into the tank. . .a beer style changes flavor. . .an actor starts making terrible films) but most reviewers understand that a few notes/reviewss/missives have a shelf life and are not meant to last forever. . .

Sometimes it would be helpful to have this option, especially when someone accuses you of saying something you did not say (not that this would ever happen on RIA).

There have been a few times I've gotten a reply and couldn't remember everything I had sent in my message. So I would definitely find this option useful.

We have the ability to retain, respond or delete messages from others. But once a message is sent the sender no longer can refer back to it. I do not like the hassle of having to maintain a separate file on my computer to keep track of what was said to whom.