Yahoo has search engine like google, directories like google, ads like google then why not yahoo try to launch its own PR?
As of now there is no rumor that yahoo wants to introduce PR rating for yahoo doesn’t encourage any kinds of SEO game. They are neutral to webmasters as well as to their visitors.
Like Google's page rank Yahoo has a concept called trust rank. Like Google estimates value for a web page Yahoo also values. The factor both consider are different. Yahoo values trust rank to pages which do not spam. The page which doesn't spam will get a high Trust rank value.
I guess that will never happen and even if yahoo launches its PR, what will be the statistics of this PR for individual sites ? If you compare the backlinks, with google, yahoo show 100 times more than what google does. So if the PR is launched, there will be no sites in yahoo with less than PR2 or PR3.... lol !!!!! The amount of high PR sites in yahoo would also be 100 times more than what google has in their system.
No point for yahoo to run the PR if the concept is same as google And the PR seems not playing important role online, therefore, yahoo wouldnt invest money on it
Yahoo uses Bing for it's search now. It does not have it's "own" search engine, it uses Bing search results. Before it got the Bing deal, it was using Google's search results. Yahoo hasn't been a search engine in a long time. It's days of innovation are over.
Why should yahoo launches the same thing like google. Maybe they are preparing something else a new algorithm, maybe better than google.
I don't know this before what are trust ranks , But yahoo popularity is measure by yahoo position checker. on can check yahoo popularity by using this link searchenginengeine.com/yahoo-rank-checker.html.
I don't know why yahoo is not providing PR to websites but it show the yahoo position for particular site or keywords. You can check it form searchenginegeine.com/yahoo-rank-checker.html