Recipe etiquette

For all my blogging friends, here is a question for you... What is the rule about recipe etiquette in blogs? I know generally you acknowledge who you got the recipe from if you can remember. But I was thinking about starting a recipe blog for my sister and mom who are always asking me for recipes that I've tried and like but I don't want to get in trouble if it's from a recipe book. So does anyone know the etiquette/unwritten rule is there? Thanks in advance!