Having to individually set each title to install was a drag, but now the miracle of check-box technology moves us into the future. Just don't expect your bandwidth to thank you.
An official twitter came from Valve yesterday announcing the new UI option, which simply presents your Library in a list to be checked off for a multi-install.
"Turns out we missed a feature in recent Steam updates. You can now select multiple games and install them in one go!" the official Steam Database (SteamDB) account.
This year's Steam Summer Sale broke new ground and bank accounts as Steam reached a milestone of 8 million concurrent