Twitter announced they are getting into the e-commerce space with buy buttons in tweets.

You will be able to see it on select tweets as listed below: Here is a screen shot and video on how this works:

Beartooth (@beartoothband)
Brad Paisley (@bradpaisley)
Burberry (@burberry)
Dan+Shay (@DanAndShay)
Death From Above 1979 (@dfa1979)
Demi Lovato (@ddlovato)
DonorsChoose (@DonorsChoose)
Eminem (@eminem)
GLAAD (@glaad)
GLIDE (@GlideSF)
Global Citizen (@GlblCtzn)
The Home Depot (@HomeDepot)
Hunter Hayes (@HunterHayes)
Kiesza (@kiesza)
Keith Urban (@keithurban)
The Nature Conservancy (@nature_org)
Megadeth (@Megadeth)
Mike Stud (@mike_stud)
Panic! At The Disco (@panicatthedisco)
Pharrell (@pharrell)
Paramore (@paramore)
(RED) (@RED)
Ryan Adams (@TheRyanAdams)
Soundgarden (@soundgarden)
The New Pornographers (@TheNewPornos)
twenty one pilots (@twentyonepilots)
Wiz Khalifa (@wizkhalifa)
9/11 Day (@911Day)

Forum discussion at Twitter and WebmasterWorld.