Since you asked...
In the film, Joe's one-sided 'tete-a-tete' with Samantha Bevins takes place at the Shangri-La Hotel, as flashed on his medallion-pager during his earlier liason with Patricia. All hotels have a bar, and all bars have a nightly shift of customers who arrive at mid-evening, discuss various life issues, and drink until the bar closes. These are, in the United States, commonly known as "barflies". The reference is comedic, and not meant to reflect on the lifestyles of the individual Barflies.
The seven original "Barflies at the Shangri-La" are all members of the Dreamworks A.I. Talkback forum, and are responsible for the transcription of the dialogue as presented here. They are as follows, in alphabetical order:
Bibliomaniac, Curious George, Diskobolus-Player2, Pazu7, Rrri77, TheUndiscriminatoryGadfly, and Uruseiranma.
Those on the following list can be considered "honorary" Barflies, for later contributions or support to the A.I. fan community:
Laurie E. Smith, author and webmaster of "Clear and Haunting Visions"
DarkPhoenix, webmaster of "Zion Academy/AI"
Jaysdragon51, author and webmaster of "Verses of Sorrow"
Sarcasmo, author of the A.I. fanfiction "Monica", available at CHV
Skelseyc, a member of the Dreamworks A.I. Talkback Forum
Hope, author and webmaster of "Woodstock Fiction"
Danchia, medical doctor and webmaster of "A.I.: Fans Around The World Tribute Map"
Large thankyou's to Jawad, webmaster of the Dreamworks Fansites, who puts up with our shenanigans.