Heather Wright-Porto said
1 year, 4 months ago: I would reverse the question and say “How many are too many?”. With a smile I say that 
I have many customers and friends, family, that start a blog (brand new), but then told they have to have a newsletter, have to setup a facebook account, twitter account, linkedin account, and before you know it they are completely overwhelmed and want to just quit it all.
So I always recommend it be staggered for newbies 
Start with their blog, get it up and running, get into posting consistently, get comfortable. Then add Facebook, do the same. Then add Twitter or LinkedIn or YouTube…whatever social media suits their business better. One by one, add them as your comfort level grows.
Just me two cents…
Main point, just jump into blogging and get going. Have fun. Be passionate. Get comfortable. Then move on to adding more and more social networking accounts 
Heather