We've seen quite a few users who don't know what a Middleman exactly is, nor what a Middleman exactly does. A short explanation can be found below.
A Middleman moderates a trade between two users. Trades with a Middleman involved normally take place over msn, verify the Middleman's Email before trading (to make sure it's not an impersonator). With an Official Middleman there's no risk of being scammed. Without a Middleman users would need to trust eachother to complete a transaction/trade, which ends up in users being scammed.
Two of the most common examples of the Middleman Process can be found below (assuming PayPal will be used).
#1 - Accounts being sold:
1) Seller provides the account information (usually Username, Password, Secret Question(s), Email and in some cases Names / Birthdates)
2) Middleman will verify this information and edit it
3) The buyer will now send the agreed amount through PayPal to the seller
4) Once the PayPal payment has been confirmed, the Middleman will pass on the account information to the buyer.
#2 - Accounts being traded:
1) Both users will send their (complete) account information to the Middleman
2) Middleman will verify this information and edit it
3) Once done, both users will receive their new account information from the Middleman
Note1: When gamecards such as UGC, PSC or KarmaKoin are being used instead of PayPal: the Middleman will watch the code be applied by the buyer through TeamViewer or Join.me after the account/item(s) have been secured. Note 2: Virtual items (e-goods) will be sent to the Middleman in-game, same procedure for accounts applies. Note 3: When you wish for an additional 'service' (such as having the seller TeamViewed making sure he/she is logged out) you'll have to announce that at the beginning of the trade. Note 4: As for Steam account: please have SteamGuard disabled at the time of trading.
Even though this has been the case for some time now: we no longer accept PayPal payments going through us, as we don't want to be vulnerable to chargebacks.