Global unique counters for your infrastructure.
Use getnextid.com to increment your build numbers etc.
Get current counter value:
$ curl -s "http://getnextid.com/counter/your.counter.name?auth=YOUR_PASSWORD"
1
Increment counter and get new value:
$ curl -s -X POST "http://getnextid.com/counter/your.counter.name?auth=YOUR_PASSWORD"
2
Your counters are password-protected.