Although the noindex robots meta tag doesn’t stop the link benefit (PageRank : PR) from flowing through the Date Archives to the WordPress Posts (Posts will still be indexed and gain link benefit via the Date Archives links), the link benefit spent on indexing the date archives (~15% of the link benefit flowing into the date archives) is wasted!
When noindex is set the ~15% of link benefit that would normally be used to rank the Date Archives for relevant SERPs does nothing, it’s wasted!
The Stallion WordPress SEO Plugin under the Not Index tab there’s a similar Block All Date Archives** option that’s highlighted in green. The Stallion WordPress SEO Not Index feature uses canonical URLs (instead of notindex robots meta tags) to recover most (doesn’t recover it all) of the links benefit that would be wasted from using the Yoast WordPress SEO Noindex Date Archives option.
WordPress SEO Tutorial : Dated Archives
The dated archives include
Yearly Archives : Custom Archives Widget
Monthly Archives : Default Archives Widget
Daily Archives : Default Calendar Widget
The first SEO question is, do any of the WordPress date archives hold SEO value?
The quick answer is a big NO.
The dated archives are awful SEO wise, the only SEO value they hold is it’s another way for Google etc… to find the WordPress Posts (a dated HTML sitemap), BUT the SEO cost to keep them indexed and the SEO damage from the targeted anchor text (the links to the archives) isn’t worth it for a sitemap!
Everything about dated archives is SEO damaging.
To index any webpage costs link benefit, in a perfect SEO world EVERY webpage on a WordPress site would serve an SEO purpose (generate Google traffic directly) and/or serve a user purpose (a contact page for example, no SEO value, but very useful to visitors). Spending valuable link benefit (PageRank : PR) on indexing dated archives is stupid : NEVER use any of the WordPress Dated Archive Widgets.
Dated Archive title tags are awful – tend to use dates, months, years etc… which have no SEO value.
Continue Reading Yoast WordPress SEO Plugin Noindex Date Archives Tutorial