Urban Dictionary defines this as 'Not being able to be reached by standard means of communication (i.e. phone / email / txt) for a several hour period.'
This also includes social networking sites such as Facebook, Twitter, Instagram, WhatsApp etc. In extreme cases, people might choose to go even darker by deleting or deactivating their accounts and turning off their phone.
She went dark for a period of a week but she didn't delete anything. She was there but she wasn't active. I knew not to pester her with calls and messages, she just needed some time and this wasn't something I could help with. It's a time when only Ben & Jerry's ice cream can help. I gave her time and eventually she escaped from the clutches of her onesie, washed her hair and was ready to get back in the game.
I went dark once before. I went to work, I came home, I ate copious amounts of ice cream, I slept a lot, and I watched a lot of chick-flicks. As you've probably guessed by now - going dark is the result of experiencing mild heartbreak. You're not so upset that you're going to cry and get your girlfriends round and blow you're savings in the space of a week by going out and getting hammered but you're upset enough that you need some 'me' time to sort you're head out and find a new life project (even if it is watching the entire seven seasons of Breaking Bad in a matter of days).
The idea is that you keep him out of sight and out of mind. If he's still active on the social realms, he'll assume that you're out doing awesome things without him and his imagination wonders if you're over him and you're living life to the fullest rather. He'll never guess that you're actually sleeping until one in the afternoon and listening to Adele on repeat.
It's not so much about mending the broken heart as it is about damage limitation. If you were to go out to your local club and bump into him when you're full of the hooch, you're probably (experience has taught me that I'll definitely do this) going to express undying love for him, shower him with abusive phrases and wake up the next morning looking like the joker because you've smeared you're make up all over your face and be too afraid to look at your text messages or your status updates. Alcohol might seem like a good idea but it's not, it's your worst enemy!
If in doubt, go dark. It might be boring but at least it's safe.