This topic comes up in numerous threads and has been discussed lots. I am going to make a How To post now to save it keep being discussed in other conversations.
It really is quite simple. Unless its flash (ie BBC iPlayer) and then it won't work. But you can grab other things from online quite easily.If you want to download and save a You Tube video you can simply use this link http://www.youtubemp4.com/
Paste in the link of the clip you want to download and do as you normally do to save it etc. That's all there is to it.For Firefox you can download and install a plug in called DownloadHelper
Please note that there are a lot of porn sites listed in its DownloadHelper media sites listing.
Install it for Firefox and follow the How To guide and you are set. You can grab things like the Ameoba vid with this. Please don't expect the file to be full screen size. It will be the same size to view as you see when viewing it online. Small size to look at but definately decent to watch. You need ADSL/broadband for downloading these larger files. Please don't post here to ask me how to do stuff with either of these. I don't have time to post in depth how to stuff here. Sorry.
The first link is really really easy to use and so long as you save your downloads to a place you can find you should not have any problems.
The second link is a bit more tricky but I managed it without reading any instructions and grabbed stuff within minutes of downloading it. Some might need to read the How To guide but don't be afraid to mess around with it and have a few dummy runs till you get the hang of how to use it.
Hopefully this will solve the problem for people and they can download stuff.