You might be sitting on a heap of unread Facebook messages - correspondence dropped into an inbox you never knew about. Before we tell you where it is, here's a quick history lesson.
Once upon a time, if you had set your Facebook privacy settings to keep your profile in an iron fortress, the only way someone could interact with you was via a 'Poke'.
People didn't get 'Poke', and it quickly became a digital precursor to 'Netflix & Chill'. Facebook instead added the ability to send someone you weren't a friend with a message - but rather than ending up in their regular inbox, it would arrive in a little-known section called 'Other'.
Recently, Facebook changed the rules again: if you head to the message section of your profile, you'll see a new section called 'Message Requests' - which could be full of messages you never knew about.
This is Facebook's way of filtering out the spam that it fears might be sneaking into your inbox from false profiles, bots or companies that are trying to sell you stuff you don't want. However, if it's from a contact you're not friends with, their message could end up here.
Have a browse, and see if that crush from Ibiza 2011 has actually been trying to get in touch with you for the last few months.
She hasn't? Never mind...