The name of this site refers to any crypto currency other than Bitccoin. They are collectively known as alt coins, alt as in alternative.
Each of the thousands of Alt Coins has it’s own blockchain, use case and community. If you are thinking of adding any cryptocurrency to your portfolio it is important to research them fully. Check their price history and daily trading volume, if they have already been listed on major exchanges. A couple of sites you can do this on are coinmarketcap.com or https://messari.io/ or https://coin360.com/.
Are they still in the idea phase? Do they have a working prototype? Is there product already in use globally? Can their claims be verified externally to their website or social media accounts?
2017 saw a lot of growth in this space and this website was launched then to assist with more people learning about something that to many was a foreign concept.
2018 saw the price of many cryptocurrencies that saw massive growth in 2017 have massive reductions in their valuations. While the prices decreased the work continued as projects continued to move forward. Many start ups failed and some as still yet to prove themselves. Do your due diligence and only risk what you can afford to lose and if the coin you put your hard earned into delivers you could see a multiple X return. Nothing on this site should be considered financial advice. It’s set up purely as a launching pad to your ongoing crypto education.