I read these reviews before I joined two years ago. Now I'm back, and can share experience.
-Yes, there are strange people.
-Yes, there are people who aren't who they say they are.
-Yes, you can have good conversations with people from other countries, and you CAN have good language exchange.
-DO NOT join expecting to be TAUGHT the language: you wouldn't sit there and teach someone English, I'm guessing, and no one is going to hold your hand through Japanese or French.
Always reach out to people, anyone you think you'd like to talk to; lots of them won't respond, but that's okay, because some will. Usually if you get ignored, it's for the best, and they would have turned out to be shallow or not speak your language.
When you get messaged, talk about what you have in common. Definitely get to know who you're talking to - it's fun! But don't give away information until you are comfortable - the right people will understand and be wary themselves.
If someone wants a relationship and you don't, make your intentions clear. They will either accept it, or they will move on.
No pressure. It isn't primarily a dating site, so don't go asking for significant others - many other members won't appreciate that.
You're just here for the ride, so make the best of it. Celebrate the friendships, but don't beat yourself up over the losses or the weird comments. If you feel threatened, you can always report, or you can leave.
If they publish personal information about you, it likely won't hurt you as much as you think - sure, it's embarrassing, but no one uses the site anyway, so the info won't get far.
Overall, my experience has been great. Just keep an open mind and don't take anything too seriously.