People are using icons without credit. Like, a lot of people.
On Tumblr, you don't get to pick an icon for a post. So, people typically used images, usually GIFs, hosted on Tumblr to show expressions like you would with icons on a journal. Now, people have started using icons and they're coming to Insanejournal to get them. I had a role player link me to wikicon earlier as their source for icons and said they didn't know people wanted credit.