While the design of a website does not in most cases negatively affect the information it contains, a site's visual appearance can have a major impact on how researchers perceive the site's content. Flashing graphics are distracting. Are there (too many) advertisements? Are the advertisements appropriate to the context of the site? For example, you might accept a few semi-obtrusive ads on the homepage of the New York Times. Mismatched advertisements and content are a signal that revenue generation rather than the dissemination of credible information is the goal of the author or sponsoring organization. While for profit and non-profit news organizations must find a way to finance their work, keep in mind how the profit motive can affect how information is generated and presented on the web.
On the other hand, a slick, professional-looking site does not automatically confer accuracy, authority, or credible content. Making spurious information look professional and accurate is a common tactic on the open web.