By putting the ScanSoft/Nuance PDF Converter into the Do Not Scan box,
you're in effect saying you trust this program and you'll ALLOW it to do
whatever it wants on your system, and only on your own system, without
monitoring it directly. There are hundreds of thousands of programs
available including some that are malware, and a significant percentage of
these are not classified by Microsoft.
The idea behind SpyNet was that, if an overwhelming majority of members
decided that an application is either trustworthy and allowed it to run or
non-trustworthy and prevented if from running, then it would eventually
make it into classified status. How well that's been implemented is
another story and also involves digital validation signatures, but I think
that the PDF Converter is probably not used by enough people to have made
it beyond this Microsoft classification hurdle yet, and I'm afraid that
your single vote by itself won't have much effect on their classification
database one way or the other.
Here's a somewhat funny sidenote, Windows Defender's own MsMpEng.exe shows
up as not yet classified in Defender's Software Explorer. Do we put that
into Do Not Scan? ...I did, for whatever that's worth ;o)