How to kill your SEO with Flash and Silverlight: A real-time look at

My rules for Search Engine Optimization have always been straightforward and simple:

  • Publish content that is unique and relevant to your target audience.
  • Write clean html. Use CSS to lay out your page.
  • Get links to your site in other high ranking pages.
  • Do not hide your content in images, Flash, Silverlight, Java, etc.

It’s this final rule which brings me to the subject of this post. From 2007 to 2009 I managed, and eventually rebuilt, the geographic information powerhouse for Prince George County, Maryland known as PG Atlas. When I inherited the site, it was built with ActiveX, worked only in Internet Explorer, and had an interface that made the original Mapquest look like the slickest thing ever. During my work on the site, I re-built it on an ajax framework, introduced it to the non-IE world and redesigned the mapping interface.

A natural side-effect of this web-standards based approach was a web site easily indexed by search engines. I left that job not long after the new site went live and it grew and prospered on google, with no active human intervention. Google was able to use the site map to index a sitelinks listing for PGAtlas. With some human intervention, this could have been further cultivated with their Webmaster Tools.

Earlier this year, I learned that PGAtlas had been redesigned once again. Soon it would be released as a Microsoft Silverlight site. The new site had no significant new features. It simply was the “old” site, redone in a Silverlight interface. This seemed like an odd choice as Silverlight would severely restrict the availability of the site. The ajax site ran on nearly any device with a browser, from IE6 to iPad. For users that don’t or can’t have Silverlight: mobile phones, tablets & Linux computers, what once looked like this:

Now looks like this:

So what does this mean for SEO?

I had the opportunity to observe the effect of this new web site on PG Atlas’ Google ranking. In the days following the release of the Silverlight site, I tracked the Google results for the query:

“prince george county gis”

Pre Launch

This screenshot was the search result for what is now the “old” site. There are prominent sitelinks for the three main sub-sections of the site: Mapping, Parks & Recreation, Development Activities. The page descriptions are appropriately taken from the introduction copy in the respective pages. The main page description was indexed from the “Announcements” section of the home page. Note the page snapshot feature of google gives a concise preview of the page.

5 Days After Launch

Google re-indexes the new Silverlight home page. The page description now says only “Get Microsoft Silverlight”. At this point the sub-pages return 404 errors. Google has already dropped the three main sub-sections from the listing and replaced them with other, less relevant, sub-pages which also return 404 errors. Note that the page snapshot now displays only a graphic about installing Silverlight.

7 Days After Launch

Nearly all of the sub-section links have been dropped. The remaining links point to a random blank page which is still live, and to a page which redirects to the home.

11 Days After Launch

The site overall has dropped from first to third in the results. It has completely lost its sub-page sitelinks. The page title and a message to “Get Silverlight” are now the only information available when searching.


When maintaining a Flash/Silverlight only web site, the importance of the non-technology alternate page is critical to SEO. These technologies lock your content in a box ignored by all search engines. Equal attention must be paid to the non-Flash/non-Silverlight page as it becomes a guessing game of which elements in the site are most important. Every element which does not have a counterpart on the alternate page is one less search result for which the site qualifies.

If we play the above scenario in reverse, we get a detailed illustration of the advantages in replacing a Flash/Silverlight site. Following established web standards provides not only the benefits of SEO, but also expanded audience. Tablets and Smart Phones are becoming ubiquitous. Their limited support for Flash is waning and their support for Silverlight is non-existent. Even without HTML5, creative CSS and JavaScript can produce much in terms of animated intros and transitions and will be supported on any device with a browser.

If SEO is at all a concern for the current maintainers of PGAtlas, they have a long road ahead of them. The site’s ranking will only continue to drop until the non-Silverlight alternate page is re-designed. The deep linking which once existed in the site will never return. The growing tablet market it is now completely cut off from PGAtlas. It will be interesting to see what actions are taken to address these issues. For now, as far as search engines are concerned, the site remains locked inside a shiny silver box.

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6 Responses to How to kill your SEO with Flash and Silverlight: A real-time look at

  1. Brian Collins says:

    I do enjoy seeing people/businesses being bitten by their uninformed trend/buzz word based decisions.

  2. Edward Gallagher UI says:

    I agree with the author on this one. From an accessibility standpoint, it is a best practice to not restrict the user to proprietary frameworks. That is, force the use of certain plugins to have full functionality. However, I think everyone at some point in time is guilty of this due to the attractiveness of these methods and ease of creation.

    My opinion: Flash and Silverlight can create stunning interfaces, but these technologies are best used for either subscription-based services or internal intranet applications. Where in so many words, the user “opts-in.” Otherwise, use JQuery UI, for example, it can do a lot of the same things.

  3. Erik Hentell says:

    I could be wrong here, but I was under the impression that Google and Adobe were working together to make SWF files an index-able file type for Google’s search engine. I seem to remember that was being touted as far back as an Adobe CS3 release event that I attended.

    Silverlight on the other hand I have no clue about as far as indexing. I would think it would be very friendly to Bing (and therefore Yahoo as well). Can someone provide some insight on this?

  4. Matt says:

    I work with Flash devs on a regular basis and the consensus amongst them is that Google indexes only hard coded strings inside the swf. A swf within a swf won’t index either. For example, if you have a pre-loader swf in the page that loads in the main swf, then only the pre-loader is indexed. If you’re pulling your text into the swf from an xml file, it will not be indexed. The only guaranteed method is to put your important content in the no-flash alternate.

  5. Brian Collins says:

    Matt Wilber is correct. The primary swf (referenced in source) can be indexed (hard coded string and up to a very limited amount of data).

  6. nancy bhargava says:

    Obviously this information is no longer tax payer friendly. Ironic that our tax monies pay for it and we can’t access the information. I’d like to know who decided to make this change?

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