A couple months ago, the Archdiocese of Saint Louis announced that a new Archbishop had been chosen (then-Archbishop-elect Robert J. Carlson). For the announcement, the Archdiocese streamed the press conference online, then posted pictures on the St. Louis Review website of the day's events (updated every hour or two).
Pageviews for April 21, 2009 on archstl.org – note that from 8-10 a.m., the server was practically down from the thousands of hits/requests it was getting. Just before 10 a.m., I enabled the caching described below. We announced everything via Twitter, SMS, Press Releases, and the web, just after 5 a.m.
During this period of time, the Archdiocesan website had over 2,000 visitors per hour, and almost all the visitors were hitting the home page. The website (run on Joomla 1.0.x) didn't have many caching mechanisms in place, and for almost a complete hour, the website was returning server errors as the processor was pegged at 100% utilization. Something had to be done!