@alex13, drawing parallels with the dotcom bubble is easy but we need to understand why there was a dotcom bubble in the first place. Huge money went into dotcom startups in 2001 but the real problem was the penetration and the lack of monetization. So it was only a certain distance that you could go with the cash burn strategy.
The dotcom bubble was a bubble on the perceived value of the stock of these companies, and a complete lack of revenue due to user penetration, and thereby the absence of a monetization strategy. And we have come a long way now.
Cryptocurrencies and the blockchain technology tied up with them has a solid business case for making hassle free transactions, cost savings, elimination of intermediaries. The market participants (similar to user penetration and acceptance) amount into billions and possibly means trillions of transactions. And we are talking Global here. The basic business case of it is very solid here and all the altcoins and the blockchain technology are addressing problems in very existent market, and solving real pain points. So while bitcoin is consumer to consumer, consumer to business and business to business, Ethereum is making it's presence felt with it's smart contracts based distribution ledger. Ripple has taken it to a very different level with addressing the pain points of the inter-bank and cross border global settlements and payments. The adoptions are increasing, and so will the value of these cryptocurrencies. I don't rule out huge volatility in the short term, but if you are good with a long-term play, this is the legal tender of the future.
Maybe you can read my article as well and let me know your thoughts - https://steemit.com/cryptocurrency/@knowledgesausage/can-xrp-ripple-be-your-ticket-to-milliondom