Google, now more than ever, don't just want more content, they want content that they feel is quality. A site's age has an influence on that site's ranking. A site that has been around for a long time can be seen as more reputable. Plus, it gives Google a background in determining a site's trustworthiness. Basically, site age lets Google know your site is legit. Can youidentify any similarities between these sites? However, this will only affect your mobile search rankings. If you want to link to somebody but you don't want it to count as a vote (you don't want to pass link-juice), or you support user-generated content and want to deter spammers, you can use a nofollow link. Google says it discounts the value of those links. I'm not convinced they discount them heavily, but other SEOs are so they seem to deter spammers if nothing else.