I have no idea if it's legit, but it does appear as if two of the people in the main picture on the main page, are...fake? lol
These cards are designed for hardcore 'Second Life' players. They load the cards with real money in order to pay for virtual items, hence the name 'Second Card'.
Of course you can still use them for other purposes.
The guy in that thread was most likely from Poland and getting the same disposable cards that second-card do, from Bank Zachodni WBK, and selling them at a small profit.
Second-card are very flexible on how they send the cards; You can chose which courier you want and how it'll be sent.