For usability purposes, entire article thumbnail is wrapped to a link.<a href=/some_article>   <h2>Article title</h2>   <div class=summary>Lorem ipsum dolor sit amet</div></a>User needs to click on any place of a thumb and it will be redirected to article.Does this approach have some negative effect to SEO ?Another question:What is more valueable for Search Engine ?Just a link to article in articles list<a href=/article1>Article 1</a><a href=/article2>Article 2</a><a href=/article3>Article 3</a>    Or h2, wrapped to link:<a href=/article1><h2>Article 1</h2></a><a href=/article2><h2>Article 2</h2></a><a href=/article3><h2>Article 3</h2></a>    
SEO and links content
html;seo
Does this approach have some negative  effect to SEO ?I'd say it is neither positive nor negative. There's so much content in the hyperlink that whatever keywords are present are going to be too diluted to have any value. But doing this isn't bad for any reason, either.Just a link to article in articles  listOr h2, wrapped to link:Unless they're headings there's no reason to wrap them in H2 tags. Don't use markup for what it isn't for. Do things the right way, not because you think it will make search engines happy. Not coincidentally the right way is usually what makes the search engines happy.