Valuable data about key aspects of modern Scottish life is being lost in a digital archive "black hole", it has been warned.
The National Library of Scotland said online and social media coverage from the past 20 years was disappearing.
It has urged the UK government to act swiftly on proposals to give libraries the legal right to collect and store electronic publications.
Legislation passed in 2003 is scheduled to be implemented in 2013.
The NLS said there was no current formal system for preserving online archive material and some information had already been lost forever.
Examples of the first Scottish Parliament website have gone as has some material on last year's Holyrood elections.
NLS chief executive Martyn Wade said: "In Scotland and across the UK we have an outstanding and enviable written heritage.
"However, we are now well behind many other countries in archiving the web.
"It is vital that we get the powers we need to save the nation's digital memory for future generations."
He said he would like to see Scotland leading the world in making as much as possible of its rich cultural heritage available online.
Significant parts of the NLS collections - amounting to more than a million pages - are now available.
Earlier this year, the UK Department of Culture, Media and Sport (DCMS) launched a further public consultation on draft digital archiving regulations, for implementation in 2013.