Make sure you have "Allow Exposé, Dashboard and others to use the screen" in keynote preferences under Slideshow.
Then, before you slide over to Safari, press the "F" key to pause the slideshow. This prevents the slideshow from disappearing.
You can then slide over, or use Mission Control, etc without affecting the slideshow.
There is a bug here, to go back to the slideshow you have to slide back to it or click on the desktop in Mission Control; you can't click the Dock icon or Cmd-Tab back to it.
(Clicking the dock icon / cmd-tabbing will just hide the dock and menubar but not take you back to the presentation)
Also: When you get back to the slideshow, the first key press or mouse click unpauses the presentation, so you will have to click / press again to advance to the next slide.
Side note: instead of having keynote and Safari on separate desktops, you can have them both as fullscreen apps. This hides the Dock and Menubar, so when you show the web page, there is more room for it.
With CrazyTalk7 you can output your creations as videos or images in different sizes, resolutions and file formats. You can convert your work to an AVI file in DVD, HD, iPad and iPhone quality. You may also convert it into sequenced image (BMP/JPG/TGA/PNG) files to broadcast on a web server.
If you wish to import a photo or movie into Keynote the most convenient way to do it is by dragging the file directly into Keynote. Just drop it onto you slide.
You can also import media by choosing Insert > Choose from the top menu.
Hope this helps answer your question.
If you have any further questions please contact Reallusion Customer Support directly using the link below. The support team will gladly help you.
http://www.reallusion.com/CustomerSupport/User/QForm.aspx
Best Answer
Go to Play → Record Slideshow and click the Record button at the bottom to begin.