As soon as you find something good and of value there will be people out there trying to take it away from you. Many of these people have been out there stealing and scamming for decades. They are much better and scamming then you are at catching scams. Your best defense is to inform yourself of their tactics so you can recognize when you are being targeted. 

You will very quickly notice that most of these scams require you to take an action that will compromise security of your ADA. One of the more common ways this is done is trough phishing websites offering fake giveaways or fake wallets. One piece of information that you should always keep in mind when trying to figure out if something is legit or a scam is that: THERE WILL NEVER BE AN OFFICIAL CARDANO ADA GIVEAWAY! 
If you find that something just doesn't seem right go to Official Resources Page and check official sources before you end up just another scam story. 

You can watch a couple of videos from the creator of Cardano talking about these scams. Just hearing about these scams can help you identify them before you become a target. You will eventual learn which non official sources you can trust. Until then best strategy you can have is to only engage in transactions that you are 100% sure about and don't tell people on line or real life that you own crypto.
So, now with that information you go about your day, check out some website, watch some YouTube and then... BAM! You spot a scam! You realize you clicked on a fake channel and they are promoting some phishing site that will steal peoples ADA. You don't fall for it, but you see 3,000 other people are watching it and it has 500 likes. You know people are getting scammed! What do you do? You give the channel thumbs down, but there is still more likes. You try to comment, but comments are disabled. You are part of Cardano world now, you are not just gonna sit there and watch your Cardano community get robbed by some looser that chose to fuel his life with misery of others! Lucky for you that you read this page and informed yourself how to strike back and defend your Cardano community from scammers. Below I will show you a few things that you can do right away to help stop and/or prevent this scam in Cardano community.
First thing you can do is report that site for phishing on Google. Phishing is any type of online activity where attacker pretends to be legitimate source in order to lure user of that legitimate source to willingly surrender their info or assets. You can report them here: Google Safer Browsing Website 
​You can see example page here. All you have to do is write down name of the website in URL field. Write out reason why you are reporting them. Then click I'm not a robot and submit the report. You don't have to sign in or sign up. Very easy and quick. 

After that you can go to ​Cardano Fraud Detection Bureau at: https://cfdb.atlassian.net/servicedesk/customer/portals and report there. They seem to be very effective and quick at taking down scam websites. 
Another thing you can do is report it directly on YouTube. For that you gonning to need to sign up for YouTube account, if you already don't have one. Once you are signed up, there are actually 3 ways to report a scam. 
1. In your list of videos you will see 3 dots on the right hand side of the screen. Click those dots (image 1) and menu will open up. Select "Report" on a bottom and another menu pops up (Image 2).  Select "Scam or Misleading" click "Report" and "Done". 

2. This way will take you a bit longer, but it seems to work better. While watching the video click little flag icon on bottom right (Image 3). Large menu will pop up (image 4). Select "Spam or Misleading". Drop down menu will open up. Select "Scam or Fraud" click next and a dialog window will pop open (image 5). Write down what the scam is and click "Report". 
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​3. If you find that channel is named and made to look like an official Cardano channel. Click on the flag on the bottom right (image 3). Except now you don't select any option, just go all the way down the menu till you hit link to "Report Channel". Another menu pops open called "Report User". Select "Impersonation" (Image 6). From the drop down menu select "This channel is impersonating someone else" (Image 7). Click "Next". Now a dialog window pops up asking "Which channel is being impersonated?" For this you need to open another tab and go to Cardano site/ channel they are faking (usually it's Charles Hoskinson's channel). You can find list of official Cardano YouTube channels on resource page here. Copy channel address and paste it in the dialog box. Another dialog box open up asking for addition notes. Just write down that content is stolen from reported channel and is used to scam people. Click "Submit" and you are done. 

​-Neo
If you have good timing you can sometime see videos being taken down in real time after you report them. It will say video not available. Then you know there were other Cardano members fighting along your side to help the community.