Gary Fenton, from Stevenage, developed Online Watch Link, otherwise known as 'OWL', so that volunteers could exchange information with local law enforcement.
It is now being used by five police forces in Hertfordshire, Staffordshire, Gwent, North Wales and Carmarthenshire, with tens of thousands of members and millions of messages being sent across the network.
"The OWL software not only helps people feel more empowered in their local communities, its also providing real results with crime rates falling in the town," the Prime Minister said.
"By supporting local people to take action on the issues that matter most to them, OWL is an important part of creating a community everyone can be proud of."
Inspector Paul Lawrence of Hertfordshire Constabulary said the website helped communities to "better look out for each other".
"This is at the heart of what Watch schemes are all about," he said. "OWL is a very effective tool that has clearly gone a long way in doing this and helped in the effort of the police and public to tackle crime."
Fenton said the website was for more than just crime reporting. "We are also used by Fire and Rescue, Trading Standards, the elderly community (helping them to be aware of scams, flu jabs or fuel allowances) flood alerts, school alerts and finding missing people," he said.