Hi,I rank high on google for some of my core keywords, but i am nowhere in it for yahoo at all. What issue might be related to this? Belows are my hypothesis,

1. it is because spammy sites link to my website, so I've got blocked from yahoo.

2. Cloaking / lifting copy?

3. Duplicate contents?

4. All of these

5. None of these

What would be the best possible answers to this?

Pay attention to the on-page optimization of your website for Yahoo. Google gives much weight to links but Yahoo gives much weight to on-page elements such as title, meta tags, H1 tags, keyword density and internal linking structure.

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SEO Technology

google and yahoo using different alogrithm for they search engine. but, you can use google Webmaster Guidelines (google.com/webmasters) for optimize your page. also make sure you don't post a duplicate content. change it a little bit. but (IMHO) it is difficult to be number 1 in yahoo, because they offer pay submission, so i think they will care for paid submission than free submission.

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Music Search Engine, Free Celebrities Wallpaper

How old is the site? I've noticed that it takes my sites much longer to get into Yahoo than Goolge. Yahoo likes site that are 6 months or older.

Thats what I have found too, It's easier to get a new site into the index in Google and Google depends way more on outside links than Yahoo which relies heavily on some old school optimizing.

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jeep web forum

None of these. Yahoo ranks sites differently than google. I rank really well on google for a lot of terms, but on yahoo, nothing. If you compare the two SE results, you will notice that the top sites are usually different.

Yahoo places more emphasis on keywords in the domain or keyword in the page name.