One objection to using a rich-client technology, such as Flex or Java, is that content on a public-facing Web site using a rich-client tool may not be indexable by search engines. This week Adobe moved to address that issue by offering to the major search engines versions of the Flash player to allow search engines to crawl content embedded inside Flex components. Searchable content in Flash files includes both text and embedded URL links.

According to David Wadhwan, Adobe's vice president of platform business:

The openly published SWF specification describes the file format used to deliver rich applications and interactive content via Adobe Flash Player... Although search engines already index static text and links within SWF files, RIAs and dynamic Web content have been generally difficult to fully expose to search engines because of their changing states, a problem also inherent in other RIA technologies... We are initially working with Google and Yahoo! to significantly improve search of this rich content on the Web, and we intend to broaden the availability of this capability to benefit all content publishers, developers and end users.

Adobe's Ted Patrick notes in a related blog post that:

The project runs SWF files within web spiders and allows all contents within a SWF file to be read by both major search engines. The cool part is that this also covers dynamic data loaded in from requests to a server, these are typically ignored in both AJAX and SWF applications... The net result is that SWF as a file format is now fully searchable by spiders at Google and Yahoo!... This enables deep exploration of RIA content both static and dynamic to occur. It will take time to see how it gets implemented in each spider but SEO [search-engine optimization] enabling SWF content is no longer a hard "it can't happen" barrier.

According to Google's official blog on search engine optimization, this technology will index text inside Flex applications as well, which are Flash files, but some limitations remain, mainly around how the Flash file gets inserted into an HTML page:

We've improved our ability to index textual content in SWF files of all kinds. This includes Flash "gadgets" such as buttons or menus, self-contained Flash websites, and everything in between...

We've developed an algorithm that explores Flash files in the same way that a person would, by clicking buttons, entering input, and so on. Our algorithm remembers all of the text that it encounters along the way, and that content is then available to be indexed. We can't tell you all of the proprietary details, but we can tell you that the algorithm's effectiveness was improved by utilizing Adobe's new Searchable SWF library...

All of the text that users can see as they interact with your Flash file [is indexed]. If your website contains Flash, the textual content in your Flash files can be used when Google generates a snippet for your website. Also, the words that appear in your Flash files can be used to match query terms in Google searches...

In addition to finding and indexing the textual content in Flash files, we're also discovering URLs that appear in Flash files, and feeding them into our crawling pipeline—just like we do with URLs that appear in non-Flash webpages. For example, if your Flash application contains links to pages inside your website, Google may now be better able to discover and crawl more of your website.

Among the limitations are that Google, and presumably other search engines as well, don't execute JavaScript code. If a Flash file is placed in an HTML page via JavaScript, then that file won't be loaded by the search engine, and hence it won't be indexed as well. In addition, external resources loaded by a Flex application, such as XML data, will be indexed, but that data won't be considered part of the Flash content. As well, not all such indexing works well with bidirectional languages yet, such as Hebrew or Arabic languages.

Do you think that making Flash files indexable will make Flex a more viable technology for public-facing Web sites? And do you think that a similar technology for Java would make applets more popular with developers?