There are two things that every modern professional must have to own their destiny:
A mailing list
Why do I say that?
If you leave your connections, friends list, professional network, followers, fans, etc., in the hands of some corporation and its service, you are vulnerable. You are at its mercy.
What will you do if that service fails and they lose all of your information (e.g., your LinkedIn connections)? Sometimes you can download that info to have a backup, but there may be nothing you can do with it without using the original service (e.g., LinkedIn doesn’t provide email addresses for your connections).
Poof! The connections you’ve built up over the years are all gone.
What will you do if a service decides to suspend or terminate your account (e.g., Facebook)? What happens if your favorite online profile gets banned and now no one can find you or contact you (e.g., Twitter)?
Bam! You just lost years and years of information that you put int…