About a hundred neighbours and members of the Platform of People Affected by Mortgages (PAH) gathered for hours in front of Mohammed’s family home, in spite of Wednesday’s heavy rain, to keep out the justice system authorities in charge of the foreclosure.
More:IPS – Defying Foreclosures in Spain | Inter Press Service
What does "platform" mean here? I think it could mean "group" or "organization" but I can't find this meaning in my dictionary.
It's stretching the meaning a bit. I think they were just looking for a word with an initial P to give them a catchy acronym (as 'pah' is an interjection expressive of disgust - as if they're saying 'We've had our bellyful of this cr@p'.