Well there is old trusty http://www.google.com
I believe drunkle already said he'd tried searching the web. I just tried myself to find a layman's description explaining what they are for, and was unsuccessful.
The way I think of the common files is basically out of sight, out of mind. They are there for a reason that I can't express well, but it probably has something to do with different programs depending on some of the same files. So Windows and other programs put them in a place that is easy to find..."Common Files".
I do look at them occasionally because some program I've installed will put their own common files in that folder. Office sure added a bunch in the Microsoft Shared folder. The reason I do take a look now and then is because sometimes a program I have uninstalled will leave behind a folder in the Common Files. So I'll manually delete it. But only if I know absolutely for sure that the files belonged to something I no longer have on my computer.
I've got a folder there now that I'm not sure of. It's Light Scribe and inside it has a bunch of files that I can tell are from Hewlett Packard. I don't remember seeing it before though. So I'm pretty sure it was probably placed there by some burning programs I tried recently and then later removed. Sometimes I can figure out where files came from by looking at the properties, but this time I can't tell for sure. So I'm just leaving that folder alone to be on the safe side.
I can tell you that the SureThing, TiVo, and Virtual Ear files look like they belong to something you have installed at some time that didn't come with the original set of Common Files after installing Windows. But if you have a Dell, Compaq, any kind of OEM install of Windows that included extra software bundles, they could have gotten there that way too.
I hope this has helped a little bit.