Multiple scammers are creating fake items that look like CS:GO, DOTA2, and TF2 items from their own worthless games, which are difficult to tell from real ones.

Update: Valve has made some interim changes to address this issue. If you see any warnings in your trade window, make sure you pay extra careful attention. Read more. Original PSA.
Login via Steam

Middleman List: 8

Warning: Scammers are copying all profiles below to steal items on a wide scale. confirm who you are dealing with before any trades. If you trade with a scammer copying one of these profiles, there is nothing anyone can do to recover your items!
Sexy Emu ☢ ジ -=SMT=-
 
2013-04 SMT MIDDLEMAN
๖Hopeless Koishi♥ ✠
 
2011-02 FoG MIDDLEMAN Banned Friends:
2 out of 794
Xristaveli
 
2012-11 SMT ADMIN SMT MIDDLEMAN
Alias
 
2006-05 REDDIT ADMIN REDDIT MIDDLEMAN Banned Friends:
2 out of 540
Enstage
 
2012-06 FoG ADMIN FoG MIDDLEMAN SMT ADMIN SR DONATOR Banned Friends:
2 out of 1837
Shubb|Need Mob App Dev (sockets)
 
2013-02 R-GOTRADE ADMIN R-GOTRADE MIDDLEMAN Banned Friends:
1 out of 781
Edward
 
2010-02 FoG ADMIN FoG MIDDLEMAN SR DONATOR
i7|Jing
 
2011-10 REDDIT ADMIN REDDIT MIDDLEMAN Banned Friends:
2 out of 383

Valve and Steam are registered trademarks of Valve Corporation.
SteamRep is hosted by the non-profit Online Fraud Prevention Foundation and is not affiliated with Valve in any way.