This post begins a new Friday series.  Each week, Yottaa CTO Bob Buffone will perform a free performance analysis of a website, chosen based on recommendations from our followers.  Please feel free to recommend a site for analysis in the comments below or on Twitter, @Yottaa!

Yottaa Score (Godaddy.com)

Yottaa has been tracking GoDaddy.com for the past two years with our monitoring system. As you can see in the line chart above, GoDaddy’s Yottaa score varies wildly.  You can also see that over the last year, it has gotten better overall, peaking in mid-July and declining a bit over the last few months.

Why the Improvement?

First, let me explain the Yottaa Score.  It appears to be a simple number between 1 and 100–and it is–but it’s also the result of a complex mathematical equation that factors in “Time to Interact,” “Time to Display,” “Time to Title,” and “Time to First Paint”–four distinct stages in the process of a browser rendering a web page.  The equation assigns a certain weight to each of these stages in order to create a single number that indicates how the average person visiting the website will perceive the performance of the website. The higher the Yottaa Score, the faster the website seems to download to the average visitor.

So why has GoDaddy’s Yottaa Score gone up over time?  The shortest answer is, simply, that they’ve been working hard to make it happen through manual optimization.

In the graphs below you can see two aspects of the page optimization have changed over the last year: Page Size and Asset Count.

• Page Size – Total number of bytes that are downloaded from the Internet when the pages are displayed.
• Asset Count – The number of different requests the browser needs to make to servers in order to display the GoDaddy.com homepage

Godaddy.com (Page Size)

Godaddy.com (Asset Count)

These graphs show that over the course of the last year there were 3 major optimization events:

• – 6/30, 2011 – The website reached a high of 71 assets and was optimized to 52 assets. The page size remained the same.
• – 9/14, 2011 – The website had 63 assets and was optimized to 49 assets. This event also reduced the page size from 449KB to 321KB.
• 1/5-1/8, 2012 – Over the course of 4 days the website was optimized from 38 assets to 25 assets, but the page size increased from 478KB to 609KB

It appears GoDaddy knows that one of the best places to start optimizing a website is to reduce the number of requests.

Another Step Deeper

You may be wondering why page size didn’t always decrease when the asset count did, and especially why sometimes it got worse.  The reason for this is that size and number of assets are independent: when you optimize your page and bundle 5 JS files into one, for instance, you will not automatically decrease the size of the content. In some cases, decreasing the number of assets can actually increase the page size, as is the case when using dataURIs to embed images into HTML and CSS.

You may also have noticed that after the first optimization event the asset counts grew, posing the need for a second and third effort.  This is something we even had trouble with here at Yottaa before using our Site Speed Optimizer.  Basically, optimization takes a lot of effort to do by hand. You may put a lot of effort into it and you get to the point of saying “good enough.” But when you shift focus and start working on other things–adding more functionality, addressing marketing needs with Twitter and Facebook, and adding more tracking tags–you inevitably add more assets to the site.  In many cases, a month after optimizing, a site will back to where it was before.

Finally, GoDaddy.com didn’t always get faster after optimization. We can see from Yottaa Score chart above that there page load times are very unstable. Comparing Google’s  and GoDaddy’s Yottaa Scores over the same period, you’ll notice that the variance in Google’s data is much tighter. This will typically be a result of the network, application, and server performance.

Google.com Yottaa Score

Godaddy.com Yottaa Score

This is all to say that manual web performance optimization is hard.  So many factors affect site speed that it can seem like a many-headed hydra: fix one problem, two more pop up.

Single Case Analysis 

Below is the chart of the Time to Interact, the final stage of our 4 Yottaa Score components.  You can plainly see a few very big spikes in the time it takes to completely load the web page. Let’s dig into the data and see why the spikes occur.

Time to Interact (GoDaddy.com)

Below is the “waterfall chart” for the red spike seen on the right side of the graph. See the BIG gray bar near the bottom?  That represents 1.68 minutes that it took to load a 33KB image. What could be the problem with this one image?

Let’s find out where they are loading the image from, using the Unix DNS tool “dig.”  You can see from the screenshot of the output from dig that GoDaddy is using a well-known CDN vendor to deliver their content.

Dig of img1.wsimg.com

Even though using a CDN is a good way to increase the performance of a large website like GoDaddy.com, it doesn’t mean that the CDN will not have problems of its own. CDNs focus on the location of your assets in the world. They will copy static assets of your website to different datacenters, which will shorten the load times of the asset. This will have maybe a 10% improvement on your page loading time.

We can see from further data that there is a lot of variation in the load times of the website and it is a result of a few assets.

• Two large images (75798_sprite_header_footer.png, )

 Speed Chart Good Performance

Speed Chart Bad performance

• 3rd Party seals.websiteprotection.com – The assets sometimes takes up to 4 seconds to load. You can see in the yottaa speed chart below that the image took 20.5 seconds to load.

Interesting Fact:

GoDaddy.com is built on Microsoft’s ASP.NET.  They currently have three IIS server versions in production:

• 7.5 – Serves the home page and static assets
• 7.0 – Serves the image.aspx file
• 6.0 – Serves the static assets