I'm a solo cruiser and am participating in my second Cruise Critic Roll Call. My first experience as part of a CC Roll Call was good. We all got together (we arranged it ourselves) the first day on the ship for drinks. Some people dined together in smaller groups and we regularly sat together on deck during the day or in a lounge in the evening. It was the best of both worlds, time to myself and time with people when I wanted company.
The second CC Roll Call is much more lively and are planning activities together off and on the ship. A group that is dining together has asked me to join them and I've accepted. There are 80 people registered for the Meet & Mingle. Will we all hang out all the time? No. But then I don't expect that.
As a solo cruiser I meet people all the time on the ship and off but it is nice to have a base of folks to start the cruise off with.