There is no getting away with quoting the 1953 Harvard Goals Study (it never happened) or the "7% of communication is words" (untrue, and disowned by the original researcher, Albert Mehrabian).
Of course, not everything on the Internet (or in Wikipedia) is true, but it's easy to verify if things ever took place. So whenever you start a sentence with "Studies have shown that..." or "It's well-known that...", you'd better be sure of your ground. If your statements can't be verified, your credibility is gone.
So my advice is to be your own fact-checker. Look up everything you claim in your speeches, and be prepared to deal with the consequences of your audience doing the same. It used to be said that you could fool all the people some of the time, and some of the people all the time, but not all the people all the time. These days, you can't fool any of the people any of the time.
Picture Credit: Creative Commons license