Can Social Media be Censored?

[Alex]

They can hinder it sure. It's usually just by brute force - in countries where the ISPs are government-run, they just block access to certain websites entirely. It's still possible to circumvent it though by things like proxies, SSH tunneling, and satellite connections, though during the Arab uprisings, some countries tried to block the internet entirely. The Chinese use a slightly more sophisticated system that scans packets for certain keywords and can then cutoff connections. This allows access to most of the site, just not the part the government doesn't like. That could also be circumvented by using code words.

Websites do sometimes censor. China requires sites to censor according to their rules if they want to have any physical presence in China, so some companies do self-censor, at least on the Chinese versions of their sites. Google used to censor, but stopped in protest in 2010 after some Chinese hacking incidents involving Gmail. I'm not aware of any self-censorship during the Arab spring uprisings.