List of members of Less Wrong who are on Twitter:

• Eliezer Yudkowsky
• Steven Kaas
• Vladimir Nesov
• So8res
• Alex Vermeer
• Robby Bensinger
• Roman Yampolskiy
• atucker
• Peter de Blanc
• Nick Tarleton
• Michael Vassar (alt)
  
• Frank Adamek
• Kaj Sotala
• Zvi Moshowitz
• Katja Grace
• Michael Curzi
• HonoreDB
• kevin
• Michael Anissimov
• ciphergoth
• Shannon Friedman
• ggreer
• fiddlemath
• quanticle
• patrissimo
• William Eden
• Divia Eden
• P.J. Eby
• Julia Galef
• Sniffnoy
• John Maxwell IV
• lukeprog
• paper-machine
• lsparrish
• Morendil
• Will Newsome (alt)
• Gabriel Duquette
• MBlume
• thomblake
• Silas Barta
• mindspillage
• Johnicholas
• RobertLumley
• TGGP
• Paulovsk
• arundelo
• GuySrinivasan
• Nic_Smith
• Chris Hallquist
• Karmakaiser
• Konkvistador
• Alicorn
• gwern
• aaronsw (deceased)
  
• Eric Herboso
• Michelle_Z
• Paul F. Christiano
• Carl Shulman
• Marcello
• khafra
• atucker
• Caspian
• NoisyEmpire
• ata
• Liron
• peter_hurford
• drethelin
• Rubix
• apophenia (alt)
• Cyan
• simplicio
• Yvain
• Hariant
• Davidmanheim
• James_Miller
• nickernst
• Louie
• Valentine
• amywilley
• Andrew Rettek
• Pablo_Stafforini
• David_Chapman
• malo
• juliawise
• abramdemski
• rhollerith_dot_com
• Jayson_Virissimo
• nyan_sandwich
• pwno
• Alex Mennen
• Brienne Strohl

Twitter accounts by people who aren't really "LWers" but recommended for LWers anyway:

• "Weird Sun Twitter"
• Robin Hanson
• MIRI
• Paul Graham
• kenzo
• Alexander Poddubny
• j.
• Kim Kierkegaardashian
• Gate of Heavens and Gap of Gods (erstwhile Catharine Evans)
• St_Rev
• Aaron Haspel
• Instance of Class
• Member of Species
• nydwracu
• Shreeda
• Razib Khan
• Jenny Holzer
• Jason Roy
• Peter Norvig
• Sark Julian
• muflax (pbuh)
• Robert Wiblin
• Sister Y, sarahdoingthings
• Anders Sandberg
• Geoffrey Miller
• admittedlyhuman, fakeysaysthings
• Possible Views
• whales
• Silas Dogood
• Max Tegmark
• Byrne Hobart
• Steve Omohundro
• Bret Victor
• Grognor

If I missed anyone in either category, let me know. I'll keep this updated.

Last update: May 18, 2015.