It's a scam site. Here's why:
1. The messages you receive are too complete. When you join you will start to receive messages from girls that match your past search criteria. If you have ever used a site like match.com, you know that most people will send a message of just a few lines. Every girl on amolatina sends a rather well written letter. Not conclusive, but it starts to raise questions. Keep in mind, the site makes money when you send a message to a girl; so it's in their interest to encourage messages.
2. Many of the pictures are too professional. To me this suggests from marketing effort. If they pictures are extremely attractive you are more likely to send a message which again is how this company makes their money.
3. Many of the girls are "online" 24 hours a day. This is the biggest red flag. No one is sitting at home all day waiting for a message from a stranger, unless it's literally their job. I'm sure, and i've read elsewhere that there are kickbacks to agencies who's girls write letters.
It's tempting to ignore the warning signs, but taken together there is a really high chance that this site is a complete fabrication. It is far safer and wiser to simple travel to these countries and meet girls there. Heck you might even do well with the amolatina tours. It's much harder to scam a face to face meeting.