Please do not quote the entire first thread.
These are not illegal, they ARE the links to Microsoft's official distribution partner Digitalriver. One link is included for the specific language, version, and bit-size, along with a product key, when you buy W7 digitally from Microsoft.
NOTE: I have heard Microsoft is not happy the various links have all been gathered together and posted on various websites around the internet but so far they have not requested we remove them.
If you do not have a product key it is extremely dangerous to buy "just a key" unless you do it directly from Microsoft/Digitalriver. Keys bought elsewhere online could easily be distributed to multiple people and can show up valid for as long as 4 months before Microsoft shuts them all down ... often too late to try and recover your money.
I would suggest these ISOs are more for people who already have a legal product key but either lost their DVD or it came preinstalled, maybe on a separate partition, and they do not have an actual DVD. It is also useful for people who received OEM installs and would rather reformat and install without all the bloatware companies are paid to force into their builds.
One further note: if you are downloading the ISO, I would suggest you download the SP1-U Media Refresh editions (see post #27) rather than the ones in the original post. The originals work for about 99.99% of the computers but if you are in that .01% you will need the media refresh version, so why even chance it?