Will Website Update Announcements Hurt my Blog's SEO?

90% of the time adding more content won't hurt your site's SEO score. As long as the information is relevant and doesn't seem "spammish", you should be fine. Regular updates are good for most sites, especially blogs. However, if you constantly add and delete content on a site, over and over again, it may set of flags to Google's crawlers and have a negative impact on your search rankings since Google may interpret that as attempting 'SEO manipulation'..