If you will excuse a little self-indulgent, self-congratulatory ballyhoo, NHS Networks has reached a significant milestone. This month we are three years old.

Our register of networks, the only comprehensive list of health networks in the UK, was launched on 1 April 2005 with just four pages.

Over the next 36 months, the register grew steadily and, just short of our third anniversary, we added our 500th network, the Greater Manchester special care dentistry - learning and support network.

We would have hit the big five-oh-oh last year, but along the way about 30 networks closed or disappeared in mergers. That is the nature of things. Now that we have 500, our short-term goal is to reach 600 and ultimately we want to break 1,000.

But it is not just about numbers. The number of networks in our register is not an end in itself but an indicator of our success in making connections. That is what a network is, after all: a bunch of connections. And as the "network of networks" - a meta-network, if you will - we create connections to, from and between networks.

Stepping back

Now that we have reached 500, it is time to take stock of some statistics and examine where networking is strong and where there is room for improvement. For example, we have always been short of dental networks, which is why our 500th network was so warmly welcomed.

The largest group of networks in our register is our group of 36 maternity/neonatal networks, although it is debatable whether they should be seen as one "theme" or split into two. Categorising networks can be tricky.

Every network has its own unique remit, serving the network members (and often a broader audience of health professionals and/or patients) in the way that is most appropriate. Networking is not prescriptive. If networks were required to fit into predetermined structures, they simply would not work. It is the flexibility of this most flexible format that gives it its strength.

Looking down the list, we are also strong in the areas of cancer, cardiac, children and young people, clinical research, critical care, mental health, nursing, primary care and public health. Some networks fall into more than one category.

But there is no category where we can say for certain that we know about every network because there are always more networks out there, especially given that our remit extends into Scotland, Wales and Northern Ireland. Compiling and maintaining the register is rather like painting the Forth Bridge - it is a job that will never end.

So, it's onwards and upwards to our 600th network.