A suspiciously high number of backlinks from some related niche websites that aren’t too great in quality. In my opinion, this could be an indicator that the domain name was using a Private Blog Network (PBN) service or their own PBN to boost their authority…this blackhat tactic can work, but it places your domain name at risk and the PBN owner could pull backlinks at any time.
There's a lot of guesswork that goes into domain name investing. It's not enough to purchase domain names that are currently popular. Just like a stock, coming too late to the game won't be profitable. You have to think of the future, instead. What domain names might be profitable in the future? Is there a new product or service that may become a huge hit? Where is the future headed?
The domain name industry is quite similar to the real estate industry in a lot of aspects. There are end users, brokers, consultants and domain flippers or “domainers”. Domain flipping works similarly to buying a house, renovating it (or even sometimes just sitting on it) and then selling it again at a higher price point. The gist of it is: you’re purchasing a domain name and betting it’s worth (or will be worth) more than you paid for it. If you’re right, you get a nice paycheck and move on. Those who make a living out of this just rinse, repeat, and scale.