Social Media, quality or quantity?

The popular rule of thumb with social media is to update, and update often. X number of tweets per day, week, whatever. I can't help but doubt this, though. I get annoyed when an organization floods my newsfeed with banal, meaningless posts, and I'll unsubscribe from their updates very quickly when this happens. It seems to me that it would be more effective to have fewer tweets but of more significant or interesting information. As far as my friends go, I perk up when I see a post from someone who rarely writes updates, and I pay more attention to those, than to those posted by people who update all the time. Sure, you don't want to go two months without an update... but it's probably ok to go two hours. Or days. Or even two weeks, perhaps.