A client of mine wishes to display the amount of subscribers on their website. They would as well if possible like to filter this by some of the custom fields. So they can show what subscribers are interested in / fields they have filled out.
Have you looked into our API? We have a method called Client.GetSegments which will gets a list of all subscriber segments for a client.I imagine a developer could use this data to get a total count. http://www.campaignmonitor.com/api/method/client-getsegments/