When you "lift" an idea from someone else is that stealing?

In this age of cut and paste, post and tweet, I think we share ideas. If you say something worth repeating, my rule is to repeat the quote and credit you. After I do this 3 times, it's mine!
 
Here's an idea from a blog I read regularly, Holy Kaw, by Guy Kawasaki. Please note that there are 2 degrees of separation because he's quoting from Merlin Mann's 43folders.com!