Social apps are growing fast. Over Facebook, Badoo and Twitter there are other good trending apps that allows to meet new people:
IMO (iOS, Android)
a public chat where you can leave broadcast messages, other people can join them or tag, you can also send private messages. The system point is enough limiting.
Some nice features are: attach pictures (both public and private), share location (pm), record voice messages (pm), make audio calls (pm).
Moco (iOS, Android)
search with filters, search people nearby you, there are games, MatchMe to easily find someone
Skout (iOS, Android)
nice interface, leak of detailed search criteria, be aware of fake profiles, heavy push on in-app purchases
Tagged (iOS, Android)
a fast growing social network, customizable profiles, tag with picture, a great number of apps included games, ads is little intrusive, lacks enough protection against spam bots.
MeetMe (iOS, Android)
easy and simple interface, there are games, over 90 millions people