I had to sign up just to add, I've been having this problem recently as well and I'm fairly certain that my computer is free of malware, but when I'm on the writing.com site, the browser will occasionally redirect to a crackle.com full page ad, and it will try to redirect several times if I simply hit the back button. I have to actually go back to the page before I hit whatever link that opened it up, and click it again, and sometimes it will send me to another crackle.com or sometimes it will simply open the link it was supposed to.

Maybe a check on the content of some ads' coding is in order?