This is a thread to collect businesses, websites, software, and other projects which use the .001 bitcoins unit
in any form or under any name. There are two categories: sites/projects/software that
support mBTC/mXBT, and sites/projects/software that
default to it. Entries in the defaulting category of course also support the unit, but for obvious reasons they are not listed twice. To start off the list we have:
Sites, projects, and software which default to displaying prices/values in mBTC/mXBT:BitBrew (Sells coffee for bitcoins)
BTC Tip (sending bitcoins on Twitter)
CoinChat (web chatroom)
coined.co.nz (Sells bitcoins for New Zealand Dollars)
mXBT.org (mXBT price ticker)
Operation Fabulous (advertising service)
PLAYTIN (online Bitcoin casino)
Seals with Clubs (online poker site)
Sites, projects, and software which support displaying prices/values in mBTC/mXBT:Bitcoin-Qt ("standard" Bitcoin client)
bitcointip (popular Reddit tip bot)
Blockchain.info "My Wallet" (popular online wallet)
Electrum (Bitcoin client)
Raining Bitcoin (advertising service)
Rugatu (Q&A with bitcoin rewards)
Post more in the comments, I will add them here.