Both Yahoo and Google already have partnered in the past over PDF indexing; this has helped Google spidered more than 214 millions PDF documents until now.
Web developers have flocked to Rich Internet Applications or RIA's that use Flash file format to deliver content and the lack of any search friendly feature in Flash meant that thousands of websites had to rely on makeshift solutions for search engine optimisation or become invisible to the search engines.
The announcement means that millions of RIA enabled websites will be immediately visible - and therefore searchable - on search engine without any intervention from web developers.
Microsoft has been excluded from the list of partners seemingly because they are working on a Flash competitor called Silverlight although some news sources say that they had been talking to different groups within Microsoft but that the talks broke down.

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