Why do authors/sites insist on doing this I suspect that apart from the uncontrollable desire to add something that is perceived to add some aesthetic value to

Why do authors/sites insist on doing this I suspect that apart from the uncontrollable desire to add something that is perceived to add some aesthetic value to the article, that there is some precedence to these enlarged excerpts actually resulting in increased readership. I don't have data to back this up, but I know that David Ogilvy regularly discussed his almost formulaic use of serifed bold headers, slightly smaller, bold subheaders, and images because they were shown to increase the readership of his advertisements. My guess is that these are used for a similar reason.