hi guys i want o know what are major algorithms modified recently in Yahoo seo which makes a bulk changes in optimization?
I don't find Profitable to optimize site for Yahoo. Now a days very few people search on Yahoo. It is best to optimize site for Google.
You're really not going to be able to find specific search algorithms. You can usually find more generic information, such as which search engines weigh which tags higher, but it's usually based on the best guesses of successful SEO webmasters. However, optimizing for Yahoo really isn't that different than optimizing for Google or any other search engine. Provide lots of high-quality content, get a bunch of backlinks, optimize your content and your page titles, etc, and just generally build a well-known authority site, and you'll see results with Yahoo.
Usually Google is pretty good about getting some information out about it algorithm updates. I don't know that I have ever seen anything for Yahoo but I haven't really looked either. It isn't an engine that is high on my list for best use. But, regardless, Bing and Yahoo did join forces in Nov. so I suspect some big releases might be occurring soon. I don't know if the releases will go public but it seems that if Bing/Yahoo wants traffic they would want to release this type of information so that SEO can be performed and ranking in Yahoo/bing would/will mean something to those who perform this type of work.
Yahoo! recently kept a notice in their site explorer page about the changes in their algorithms source: http://siteexplorer.search.yahoo.com/index.php