I hear it often, and can usually derive a sentence's meaning with or without it. What does it really mean? When would one use it?
It means 'whether or not this is of any use/value'.
For what it's worth, I'm very sorry I broke the window.
means, for example, that it may not make any difference to the physical state of the window, but that hopefully the apology helps placate you.
It's almost a kind of self-deprecation; it's saying 'No words of mine will be adequate, but...'
1I would not say that the value of the apology is being interpreted in relation to the current condition of the window, but in its relation to its effect on the owner of the window, to whom you are apologizing in a manner which clearly indicates that you know you owe more than just words for the breaking of that window. May 26, 2011 at 2:51
@Runeslinger, I think it also implies that while you owe more than these words, these are the best you can do. A better example would be "For what it's worth, I'm very sorry I let your secret out". Is that right?– recluzeFeb 15, 2012 at 2:02
for what it's worth (informal)
said when you are giving someone a piece of information and you are not certain if that information is useful or important.
Cambridge Advanced Learner's Dictionary
for all or for what it's worth; for whatever it's worth:
Even though it may not be important or valuable.
For example, Here's my opinion, for what it's worth, or For whatever it's worth I've decided to take the train. [Late 1800s]
As reported from the NOAD, for what it is worth is used to present a comment, suggestion, or opinion without making a claim as to its importance or validity.
For what it's worth, she's very highly thought of abroad.