Pros
It's a global digital marketing network, owned by WPP Group. I worked in the Singapore office. Nice working atmosphere, mostly nice people at the time, drinks after work on Friday. I believe there was quite turnover at the time so I'm not sure how it is now.
Cons
POSSIBLE was formed from 8 or 9 different digital agencies from around the world that WPP acquired, with very different specialities, management, clients, etc. When I joined, in my opinion they were still struggling with the growing pains of the transition and merger. More specifically for the Singapore office, most of the work was technical rather than creative in any way and I disagreed with the way they managed teams, clients, and new business pitches. Overall, I'd say it was very messy - even though one or two people were clearly trying to make things better they had a tough time of it. There was also not enough work going on at the time and was concerned they would being making redundancies (which they did after I left). Things may have improved since then, I don't know.