However, something that was a reminder today, a spike in traffic can destroy your server if you aren’t optimized.  If you are getting promoted on television, being interviewed, or otherwise getting mentioned on a popular program that might send a few thousand people to your site at one time, be careful.  Even if bandwidth isn’t a problem, CPU and Memory might be.  If you are expecting a spike, make your home page static.  Most of your visitors will come there, and if you make it a static page (mod_rewrite them to the dynamic script if they have a logged in cookie), you’ll drastically cut your database load.

In fact, I think most sites would do well to always make the home page static.  Something we did “back in the day,” was program the whole site dynamically, then “mirror” the home page to a file with wget or something.  One could have most of their site mirrored to static files, and serve up dynamic pages to logged in users.  Historically, that’s what Slashdot used to do.

Either way, you should remember to optimize your main queries, and create the appropriate indexes as part of bring a site life.  Bandwidth isn’t the only constraint, sites without dozens of servers need to worry about CPU and memory usage as well.  A popular television show can send WAY more simultaneous traffic than social media or search engines, at least at one time.