There is a difference between posting “just enough” and losing followers to audience fatigue. Different turnover rates on social network news feeds mean you should adjust the amount of content you publish.
Because Twitter moves quickly, you can post up to five times per day. Limit your Facebook postings to five-to-10 per week. LinkedIn shouldn’t exceed 20 per month.
Don’t overload your own strategy. A rule of thumb is to begin with three to five posts per week. From that point, you can increase or decrease the frequency to find the optimal level for you and your audience.
– Patricia Mills, C2 Communications