Facts and tables are not copyrightable. The phone numbers in a phone book are not copyrightable, merely their presentation order[0]. If you were to copy, say, the linkedin website, or the linkedin branding, or the name linkedin, or any of their ads, those would be eligible, but the simple collection of names, emails, and phone numbers is ineligible for copyright.
This depends on jurisdiction though. In the European Union specifically there exists sui generis legislation that grants certain rights to the assembler of a database [1]. However, it’s a more interesting situation when the database keeper just provides a means for individuals to fill in their own data.
0: https://en.wikipedia.org/wiki/Feist_Publications,_Inc.,_v._R....