Ask HN: Should I Click the Up Button to Save or Vote?

I, like many others, use the up button on Hacker News to both save the story and show that I think it's interesting.

But what's the best way to use it/think of this button?

Are there general guidelines or does it mean anything you want?

Ultimately, if it's worth saving then it's probably worth upvoting. Content that adds value to the readership of the site should be upvoted.