It looks like Google has rolled out a new search user experience in the desktop search results. When you start typing your query and Google shows you search results, those search results will be lightened up, the transparency will go down and be less visible as you type.
Here is a GIF of it in action:
Here is what it looks like when you type, click on it to enlarge:
Then when you finish, it darkens up to full transparency or opacity:
On mobile, Google just doesn't show search results as you type.
This was spotted first by Brodie Clark on Twitter but it seems to be fully live for everyone?
Forum discussion at Twitter.
