This document summarizes a presentation given at O'Reilly's Web 2.0 Expo about ways to unintentionally slow down websites. It identifies several factors that can degrade performance, such as having many page resources, large file sizes, poorly optimized code, lack of caching, and unnecessary redirects. The presentation provides examples like excessively large images, verbose HTML/CSS, inefficient plugins, and not accounting for network variability. It concludes by stating the importance of testing site speed and using tools to identify and address performance issues.

1. An Experts Guide
to making a website slow!!!
October 13th, 2011
Presented at O’Reilly’s Web 2.0 Expo in NYC
Bob Buffone, CTO - Yottaa
Yottaa Inc.
2 Canal Park 5th Floor
Cambridge MA 02141
http://www.yottaa.com

2. Agenda
• The Web… Its complicated
• Things that make a website slow
• How can you make your website faster?
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3. THE WEB… IT’S
COMPLICATED
© 2011 Yottaa Inc. All Rights Reserved. 3

4. In between your visitors and you
Data Major ISPs CDNs Geography Last Mile Browsers Users
centers
Performance uncertainty
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5. THINGS THAT MAKE YOUR
WEBSITE SLOW
© 2011 Yottaa Inc. All Rights Reserved. 5

6. Lots of Requests
• Product owners want rich websites
– Rich in User Experience
– Rich in Visual Presentation
• Achieving richness requires more
resources to be downloaded to the client
– CSS
– HTML
– JavaScript
– Images
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7. Fat Resources
• Many of the resources that you need to
load can be made fatter than required
– HTML, CSS, JavaScript – Add lots of
comments and white space
– Images
• Use images that are larger than displayed on the
webpage
• Always use the highest quality settings
• Turn off gzip compression on your server
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8. Bad Servers
• There are many things that can make your
servers slow
– Poorly written code
– Bad database design
– Sharing a server with others
– Old Servers
– Not enough memory
– Slow hard drives
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9. Randomness
• This is one of the hard things to add your
site to make it slow.
– Some of your users will experience a slow
website
• It only takes one resource to slow down
your website.
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10. Do not use caching
• The web allows you to specify which
resources the browser will cache on the
visitor’s machine
• Not specifying cache control correctly
means the browser will need to load
resources for every page and
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11. 3rd Party Plugins
• Bloggers love to make their websites slow
using plugins.
– Twitter, Facebook, Google Plus, LinkedIn
– Photo plugins…
• Not utilizing asynchronous loading of 3rd
party resources.
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12. Other things you can do
• Redirect from www to non-www using client-side
– Use a 302 redirection instead of 301
• Add requests to resources that do not exist (404)
• Run JavaScript code while your page is loading.
• Only look at how fast your site is from your desktop
• Think your website is fast enough
• Do not test your websites performance
• Think your developers would never do any of these
things
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13. HOW CAN YOU MAKE YOUR
WEBSITE FASTER?
© 2011 Yottaa Inc. All Rights Reserved. 13

14. Yottaa
THANK YOU FOR YOUR TIME
Bob (Buffone)
Twitter: @Rockstarapps
CTO/Co-founder
www.yottaa.com
Twitter: @Yottaa
Come and check us out in the Expo Booths!!!
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