You may want to consider the value and importance of copyrighting you audio, video, and PowerPoint conference materials, especially if they are available online for anyone to access. Putting your presentation in PowerPoint rather than word makes it harder to copy and steal (adapt). You can also make your documents permission based, read-only so they cannot be edited. Be sure to include a copyright symbol on the bottom of the page, and at the beginning and end of every recording.
If you are amenable to sharing the information, as long as you or your organization is cited as the source, you can state that policy also.
The point is you want to retain control of your content and your concepts. You may even want to register a copy of your presentation with the Library of Congress (www.loc.gov) in advance, so that if anyone tries to copy or repurpose it, that you will have protection under the Copyright Act. While every document you create IS copyrighted at its inception, filing the copyright gives you protection if you have to mount a lawsuit.
By the same token, if you are using anyone else's content in your presentation, you should call, email, or write them and ask for permission to use their content. If you are just using a sentence or two, you can simply cite it with the proper attribution or website, and you are sufficiently covered.
Be smart. Be honest. Better to be safe than sorry.