Hillary has been coordinating with her Correct the Record PAC
The reason that it isn't illegal coordination is a creative interpretation of a "2006 Federal Election Commission regulation that declared that content posted online for free, such as blogs, is off limits from regulation."
https://www.washingtonpost.com/news/post-politics/wp/2015/05/12/how-a-super-pac-plans-to-coordinate-directly-with-hillary-clintons-campaign/So, while Clinton is coordinating with Correct the Record, she isn't illegally coordinating with them.
