Why does Bing webmaster tool's SEO analyzer complain about multiple <h1> tags?

Question

I used the Bing webmaster tool's SEO analyzer on my website, and it reported:

There are multiple tags on the page.

It recommends that there should only be one <h1> tag on the page.

The page is a listing of blog posts for a category. So each blog entry is structured like this.

<article>
    <header><h1><a>...</a></h1></header>
    <p>summary...</p>
</article>
<article>
    <header><h1><a>...</a></h1></header>
    <p>summary...</p>
</article>
<article>
    <header><h1><a>...</a></h1></header>
    <p>summary...</p>
</article>
<article>
    <header><h1><a>...</a></h1></header>
    <p>summary...</p>
</article>

How is this invalid? I thought this was the correct way to describe a post in HTML5.

Answer 1

Don't change your code which is valid, it's just because SEO analyzer from Bing is late and doesn't take into account HTML5 semantic.

Answer 2

Semantically, it's correct (as Zistoloen said), but logically it isn't. <h1> tags are supposed to be used as the title for your entire page, which isn't the case here. Using multiple <h1> tags sends mixed signals to search engines and it'll be less obvious for them to know what your page is really about.

I would put the category title in <h1> tags and the article titles in <h2> tags. This way, it's obvious that your page is a category overview and that the articles are logically placed under that category.

You don't have to change it, but since search engines like the structure and use it to see what your page is about, I would http://webdesign.about.com/od/seo/a/why_use_h1_for_seo.htm is an interesting read.