Mark Cuban compared the cryptocurrency boom to the dot-com bubble.br In a string of tweets he recommended buyers hedge their bets.br He warned them about the dangers of debt in a string of tweets this week.br "Watching the cryptos trade, it's EXACTLY like the internet stock bubble."br Cuban sold his startup to Yahoo in 1999.br He managed to protect his billion-dollar windfall when the market crashed a few months later.br "My advice? Learn how to hedge," he tweeted.