Starting this week, Instagram will allow people on Facebook to DM you, and vice versa. This step is the first in Facebook’s broader plan for a unified messaging system, where people can message across Facebook, Instagram, and WhatsApp. The Instagram update will include a few additional features (selfie stickers! custom backgrounds! ephemeral-but-not-encrypted messages!) for a more Messenger-y experience.

If you are recoiling in horror at the idea of Facebook contacts messaging you on Instagram, you are probably not alone. Plenty of people have very different identities and personal expressions across apps, and very good reasons to want to keep them separate. Depending on the person, the consequences of allowing Facebook and Instagram contacts to mix could range from mild embarrassment to serious harm.

For now, it’s possible to opt out of the cross-platform update completely (though this means you won’t get the other minor bonus features for Instagram DM). Even if you opt into the update, there are customizable controls where you can block all Facebook chats if you want. However, this is opt-out, and the settings are three pages deep within the “Privacy” settings of Instagram. By default, Messenger users will be able to send DMs to your Instagram.

However, if you had hopes that your Instagram and Facebook accounts were totally separate, the horse is out of the barn. If you have your accounts connected at all, you already probably see Facebook friends being suggested to you on Instagram. A Gizmodo investigation showed how Facebook has long been able to piece together your contacts based on “shadow profiles,” using contact info from phones and address books to suggest “People You May Know.” You’ve probably noticed acquaintances who aren’t even your Facebook friends show up in your Instagram suggestions for people to follow; this is why.

According to Instagram, cross-platform messaging is solving a common user problem: 1 out of 3 people surveyed have trouble remembering which messaging platform they had a particular conversation on. Of course, this solution to a user problem also benefits Facebook, which is eager to blur the lines between their apps. Unclear what percentage of people would NOT want Facebook people messaging them on Instagram — that is, if it’s more or fewer than the 1 out of 3 who would be helped by cross-platform messaging.

Ultimately, like all other minor encroachments on privacy, this change might seem horrifying at first, and then you’ll get used to it, and then the next, even-more-invasive thing will come along, the Overton window having been shifted enough for you not to be so surprised.

This new feature doesn’t change user privacy in terms of ads or user data or even who can see your profile or photos. It’s a change to your perceived privacy, in terms of whom you expected to see your account or try to talk to you. According to a 2019 Pew Research Center report, only 29% of Americans know that Facebook owns Instagram — so this new cross-platform messaging will likely come as a surprise. Whether or not those people will view this as a great convenience or a creepy intrusion, well, idk.