Let's get these definitions out of the way so there's no confusion. This is how I interpret "by," "inspired," "adapted," and copyright laws.
If I made someone else's recipe in its entirety or with minor modifications, I link back rather than republish the recipe on my blog. Example:
Turnip Cake.

Mango Chicken.
If I saw something and then made something similar, but did not go from a recipe, I'll say I was "inspired." Example:
Mango Chicken.
If I used someone else's recipe as a starting point, but made substitutions, I'll say I "adapted" the recipe and link back. Notice I don't do it half-assed by saying I got it from "here." I provide the name of the blogger and/or the blog and a link to the appropriate page. And I placed the link in a prominent location below the recipe title. Example:
Gaeng Kiaw Waan (Thai Green Curry with Thai Eggplants).
Notice in all of the examples, I used my own photos, wrote everything in my own words, and linked back to the appropriate page with the full name of the website or blog. Just because something's available online doesn't mean it's free. And no, using someone else's photo or recipe and providing a link back isn't always enough. I observe these courtesies because I know how much work goes into creating each post and want to be respectful of the blogger. I also like playing within the confines of the law.
According to the
U.S. Copyright Office, all works published after January 1, 1978 are held under copyright protection until the creator's death plus 70 years, regardless of whether or not a copyright was filed. The
Digital Millennium Copyright Act (DMCA) of 1998 further requires that Internet Service Providers (ISP) remove the copied material when notified of a copyright violation. Now, whether you can enforce these laws might require an attorney, but those are your legal rights. There are
Spam Blogs (Splogs) that will steal your photos and content, run ads, and hope to profit from your hard work.
ProBlogger has the steps he took when someone stole from him in, "
What to Do When Someone Steals Your Blog's Content - Blog Plagiarism."
Lorelle on WordPress has more detailed information on "
What Do You Do When Someone Steals Your Content."
Just because something's online doesn't mean it's free.