Just like WenRob said, its totally fine to copy a LO or be inspired by something someone else did. I do it all the time. What they are talking about stealing is buying a kit or pack of elements and then giving a copy to someone. That's piracy and its illegal, not to mention very rude to the designer who worked so hard to make the digi-products.
But looking at someone else's LO and making one thats similar is called "scraplifting" and its perfectly fine. I try and always give mention of who I scraplifted in my credits when I do that. And yes, you always should give full credit of the products you use when you post a LO online. I keep track of mine as I scrap the page so I don't forget!!
Alrighty - next post from me will be a link to the CHALLENGE!!!!