Zaqa is described as 'Question & Answer based social networking tool' and is a Social Network in the social & communications category. There are five alternatives to Zaqa for Online / Web-based, Android and iPhone. The best alternative is Ask.fm, which is free. Other great apps like Zaqa are Hawaar, CuriousCat.me, Zabuu and Peing.
Zaqa is mainly a Social Network but alternatives to it may also be Q&A Services. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Zaqa.