Skype hijacks port 80

Imagine my dismay and perplexity today when Apache suddenly stopped working on my development PC. Checking the Windows event log revealed this error:

The Apache service named  reported the following error:
>>> (OS 10048)Only one usage of each socket address (protocol/network address/port) is normally permitted.  : make_sock: could not bind to address 0.0.0.0:80

Aha! Another service is using port 80, preventing Apache from binding to that port. But what? I wondered if I had caught some terrible malware serving out who-knows-what…

However, a quick Google search revealed Skype as the culprit!