There are moves to investigate social media even before they grant you visas. Forget where I read this, but they're proposing that this becomes a part of your visa application.
Won't happen. Visas and entry requirements are a tit-for-tat affair. The crying from US citizens asked to do the same when visiting the UK/other countries will scuttle this idea.
The EU is already debating to remove the visa free status of US travelers, having the searches will surely push them to go through with it.