Sometimes, you just know someone is online on Facebook but not your friend. If you see that their profile picture has changed, or if it’s been over 24 hours since they last updated their status or posted on your wall—you should be concerned. There are many reasons why this might be happening: maybe they are at work and can’t access the site; maybe they are on vacation and forgot to log off entirely; maybe they just don’t care about seeing what you’re up to. But what if it’s none of these things? What if they’re simply hiding from you? Luckily, there are a few ways to tell if this is actually the case!

Use messenger

As you may have guessed, the easiest way to figure out if someone is online on Facebook but not your friend is by sending them a message. This works whether they’re a stranger or an acquaintance–and it’s also how you can tell if they’ve seen the message!

If they are online but don’t want to talk with you, they’ll get back to you eventually (or ignore it altogether). If they aren’t getting back to you immediately after sending a message through Messenger, there’s a good chance that person isn’t responding because they’re busy or away from their computer.

For example: Let’s say I’m looking for my friend Sam who lives in another state and has been offline for several days now. I send him an email asking if everything is okay; he doesn’t respond within 12 hours so I assume he must be busy at work or something similar (which could also explain why he hasn’t been answering my calls).

Check if their account is blocked

If you want to know if someone is online on Facebook, but not your friend, there are a few ways to do so. The first step is going to their profile page and looking at the top right corner of their profile picture. If there’s a padlock icon next to it, then that means their account has been blocked by them or another user. If there isn’t one, then it means they haven’t blocked anyone (or themselves).

Check if there is an active chat

If you want to know if someone is online on Facebook but not your friend, then check whether there is an active chat. If there is an active chat, the person is definitely online and you can start chatting with them.

If there isn’t any active chat, then it’s possible that this person has logged off from their account or maybe they’re just taking a break from using Facebook for some time now (and won’t return until later).

Look at their profile picture and make sure it’s the same.

You can also check their profile picture and make sure it’s the same. If you don’t see any changes in their profile picture, then the person may have just been busy and forgot to update it.

If they do have a new picture or look different in some way, then it could be because they changed their appearance on Facebook. This means that you’ll need to go through all of your friend list (or at least all of those who are online) until you find the person whose photos match up with how they look in real life; this will help narrow down exactly which account is theirs and not another fake one set up by someone else trying to impersonate them for nefarious purposes (or just because).

Sometimes people are online but not your friends.

• You can’t see their profile picture.
• You can’t see their status updates.
• You can’t see the people they are friends with, or any of those people’s profiles either (unless you’re also friends with them).
• You might also be able to tell if a person is online by looking at their profile and seeing that it has been updated recently, but this isn’t always true–and even if it were true, it doesn’t tell you if they’ve been using Facebook Messenger or WhatsApp instead of checking into the app itself!

So, how do you know if someone is online on Facebook but not your friend? Like we mentioned above, there are several ways to do this. You can check their profile page and see if there is an active chat with another person or if they have any notifications from Messenger that aren’t from you. Another option would be looking at their profile picture and making sure it matches up with what you remember seeing before when they were available for chatting.