Cryptocurrency projects have been popping up left, right and center in the past 18 months, but over 800 of those are now dead, adding to comparisons between the current digital coin market and the dotcom bubble in 2000.

New digital tokens are created via a process known as an initial coin offering (ICO) where a start-up can issue a new coin which investors can buy. The investor doesn't get an equity stake in the company, but the cryptocurrency that they buy can be used on the company's product. People usually buy into an ICO because the coins are cheap and could offer big returns in the future.

There has been an explosion in ICOs. Companies raised $3.8 billion via ICOs in 2017, but in 2018 so far, this number has already shot up to $11.9 billion, according to CoinSchedule, a website that tracks the market.

However, hundreds of these projects are now dead because they were scams, a joke or the product hasn't materialized. Dead Coins is a website that lists all the cryptocurrencies that fall into those categories. So far, it has identified just over 800 digital tokens that it considers dead. These coins are worthless and trade at less than 1 cent.