The death of actor Robin Williams took the world by surprise on Monday evening, and fans everywhere began expressing their grief on Twitter. Hollywood remembers Williams fondly: Judd Apatow, for instance, called him "A genius and a truly kind man who made the world a better place," while Neil Patrick Harris said he was "stunned and just reeling." 

Williams was an inspiration to many business icons as well. Here are 9 names that you might recognize commemorating his infectious on-screen presence via Twitter:

1. Marc Andreessen

2. Micky Arison, former CEO of Carnival Corporation and owner of the Miami Heat

3. Pete Cashmore, founder and CEO of Mashable

4. Daniel Gilbert, entrepreneur and Professor of psychology at Harvard University

5. Dave Morin, co-founder and CEO of Path

6. Martha Stewart

7. Bret Taylor, entrepreneur and co-creator of Google Maps

8. Ted Turner

9. Barbara Corcoran