If it's not on this list then I don't use it, so I can't accurately judge. By stalkability, I mean the ability to get to know someone, NOT actually stalking them like going to their house and watching them.
  1. Snapchat
    You can't see who they're friends with, you can only see this one snapshot from their life, and of course that's at their own discretion. There's no sharing or liking, meaning you have no clue what they like or agree with. Don't use this to stalk people!
  2. Instagram
    This one is also not great for stalking. There's one line for a bio, and other than that there's no information about the person. It's the "norm" to only post one photo from an event, and people usually wait until after that event is over to post a photo from it, meaning by the time you see it, they're already gone. There's no page to see what pictures they like, so if you want to know that, you have to go through all of their followers and check each one of their photos.
  3. Facebook
    This one definitely has the biggest section for information such as birthday, city where you live, political views, family, etc. but people don't normally fill all of that out. Plus, people don't use this app nearly as much thanks to Instagram and Twitter, so that doesn't help either. But this one gets more stalker points because other people can tag the person in photos and stuff, thus giving away things away even if the person isn't a big poster.
  4. Li.st
    Giphy downsized medium
    This one and Facebook were very tough to choose between. Li.st just struck me as more active than Facebook (at least for me anyway), thus making it easier for you to stalk them. Plus, this has a list of all of your liked lists and relisted lists, and you can go all the way back to the beginning if you want to!
  5. Twitter
    Do you want to see what someone has commented on? Just go to their page. Want to see who they follow/who they're interested in keeping up with? Go to their page. Their birthday? Yep, it's there. Their likes? Also there.