The recent plunge in the value of Facebook and other once high-flying social media stocks has brought back painful memories of the dotcom bubble of the late 1990s.
In that first wave of internet euphoria, investors threw money at unproven start-ups which quickly went bust or shrank to a tiny fraction of their peak value.
Five trillion dollars (£3.2tn) was wiped off the value of shares traded in major centres between 2000 and 2002, partly through the collapse in technology stocks.
There are parallels with what is happening now to social media shares.
Social media is the term bandied about for a range of internet businesses that have recently joined the stock market.