This is the official website for the Lamont-Doherty Earth Observatory of Columbia University. It is safe.
This is the official website for the University of Oklahoma. It is safe.
I have used this site to convert several PDFs to Word documents and have not had any problems so far.
While visiting this site I was redirected to a known malicious site. Use with caution.
This website hosts malicious downloads. Do not visit this site!