Hi LewiLewi, We met and chatted with a couple of solo travelers in the Explorer's Lounge or on excursions.  They seemed to be enjoying themselves and happy with the cruise.  Can't comment on shared tables since DH and I were always seated at tables for two by the hostesses at dinner.  We did note many larger tables especially in the Restaurant but not aware of the seating arrangements (individuals or couples wanting to meet fellow passengers or larger groups traveling together).