In the past people with slow connections who tried to watch YouTube videos often had their patience tested. Playback often caught up with the buffer, leading to annoying pauses--and leading many to give up entirely on watching Youtube videos.
Things have changed for the better, reports the Google Operating System blog. YouTube videos are now held in the browser's cache by default, allowing people to watch them again and again without pauses once they have been downloaded.
Youtube even has helpful advice for people with slow connections: "Still rockin' the 56k? No problem. As you may already know, a slower connection simply means slower delivery of services. You only need a little more time and patience than with a faster connection. For best results, you may want to start the video player and then click on the PAUSE button immediately. Then, wait until the red progress bar has reached the end of the video before playing it. Allowing the entire video buffer lets you watch it without interruption. Remember, the shorter the video, the shorter the amount of time it takes to buffer."
Even if you have got a fast connection, you may want to make use of this trick if your network seems slow.
There is, of course, nothing strange about the idea of caching Flash SWF files, even though the Google Operating System blog says that "YouTube managed to achieve something incredible" here. It seems rather to be a decision on YouTube's part to allow the (legal?) caching of videos by default.
The benefits are clear, however: better enjoyment of the YouTube videos you want to watch once or more than once, whether you have a slow or fast connection, and the ability to close and re-open the browser and then watch those videos again without having to download them a second time. Just remember, if you want to start caching large numbers of YouTube videos, you will want to make sure your browser cache size is big enough to accommodate them.
And one more thing, this new "functionality" also works for YouTube videos embedded in web pages on other sites, such as here on Neowin!