In light of the latest events concerning CNET, Google stated that deleting old articles is not going to help you better promote your website for search engines.
Deleting older articles is one of the SEO practices used by some sites to make a website allegedly seem fresher and ranked higher by Google.However, after a recent disclosure of CNET, an old and reputable web publishment performing this kind of manipulation, Google openly announced that actions of this kind are futile and are not going to lead to any type of improvements in search engine output. According to Google's Public Liaison for Search Danny Sullivan, practices of this kind may make Google pay more attention to newer publications. Still, they are not going to contribute to the general picture.
He added, that the presence of older pages does not affect the reputation of newer ones
What happened is that recently the Gizmodo publishment after some research discovered, that certain older pages on the CNET website were gradually disappearing from the website, reaching the an impressive number of articles, which seemingly was an effort to make Google “think” that the website is still completely fresh.
It’s worth mentioning that this is not the first case of CNET trying to run search algorithms around their finger.