I have come across it, it's a cryptocurrency exchange established in 2013. Not so popular but has some large number of users. You can Google search it for more information on it.
Lemmecoin is a scam exchange. They are offering huge amount of money to a random discord user then requires the user to deposit so that they can withdraw the winnings. I saw there bullshit road map on there website and anyone can fake the timeline and indicate whatever date they want to declare. Besides that, They took 7 years to build a leverage trading exchange while the feature is so poor. This is a big red flag.
I received too there PM on my discord last Dec 3. I just recently open it and I search about them until I come up on this thread.