Scam or not

I thought these social media raffles were all rather suspect.
Then I saw a fellow Blipper post a picture of a rather fabulous bike he won.
Nevertheless, I was still hugely surprised and tentatively pleased and excited when my number came up in draw for this lovely Gretsch. 
Huge reassurance when it was delivered. 
Seems a great business model for the website owners and shines more than a little brightness into the lives of the winners.