Shodan[1] is one of the most familiar site for research on what is on the internet. In Oct 2020 I did a diary on Censys [2][3], another site collecting similar information like Shodan. The next two sites are regularly scanning the internet for data which isn't shared with the security community at large.
Read the original article: Who is Probing the Internet for Research Purposes?, (Sat, May 8th)