Clicking either will allow you to watch the video as you normally would. If Flash is installed, when you click the link to download, you'll be presented with a dialogue box asking if you want to use Flash on the current site just once, or every time you visit. When you visit one of these sites in Safari, by default you'll see either a black screen with a button saying Click to use Flash or the website will encourage you to download Flash. However, there are some sites and services, such as Hulu, Spotify, and Pandora, that require the use of Flash for video playback, music streaming, and more.
