If you use Google Chrome, try ad blocker. Or (also if you use google chrome) check to see if there is an "extension" running that may cause them. There was something on DH's laptop that was causing ads to show up in the middle of posts, that I solved by removing the extension.
mmm....I use Chrome but not sure if I have Ad Blocker or not. DH is the computer guru and does stuff without me knowing. But no, I don't have anything, either.