While this is not an answer to your question, may I ask why it is a problem that someone “known” how many sites you may have? (No one will actually be able to tell the number of sites you are tracking as there might always be a site that has n+1)
The reason I would prefer not to have someone see a specific number is client confidence.
If I give a website an site ID of 3, they always think well that means I have only 2 clients before them.
It may sound like a petty reason but every little helps
My primary desire for a feature like this is so I could give it a unique code that fits with my standards as well. For example, Site ID -> 1 to Site ID -> ABCDEFGHIJK. This would allow me to script my tracking code generation as it is a known value whilst the Numeric site ID number has no reference to my other standards.
We need YOUR help! We are running a crowd funding campaign to raise funds to implement the detailed Visitors Maps of Countries, Regions and Cities (for all countries)!
These maps will be beautiful, usable, and built using open standards SVG+JS. They will show detailed visitor count, conversion rates, by Country but also (New!) by city and region.
I would also like to have a custom site ID.
Currently it is possible to find out all existing sites (by id) and create spam and other malicious things to that sites. @halfdan piwik will respond with a 404 in the tracking request when a site doesn’t exist, so you can find out exactly how many pages there are.