Key interactive areas of the Downing Street Web site were offline last week following a mysterious "technical fault".
People trying to participate in online debates in the "have your say" section were confronted with an apology for the failure, but no explanation of why it happened.
Site manager Russell Oppenheimer refused to say whether the fault was due to a hacking attack or from upgrading security. "Security considerations mean we cannot reveal details of the technical problems," he said.
Three days after the breakdown, one Number-10.gov insider admitted that the Web site team still did not know what had caused the failure.
More memory has been added to the server in a bid to avoid future difficulties and speed up the site, and a second server is to be installed to allow load balancing between the two. Downing Street and site designer Bates Interactive also used the site's downtime to upgrade software to improve user friendliness.
This includes a better navigation system for the forums and an automatic archive. However, the upgrade will mean that those who have contributed to Downing Street's online debates will find their thoughts consigned to the dustbin.
Security will be stepped up with a registration system that Downing Street hopes will "cut down on the number of inappropriate and offensive postings and a facility to bar users that misuse the site".
Finally the site administrators have registered a series of URLs on the theme of Number 10, prime minister and government in a bid to make it easier to find the site.