Yes, the PDFs would help increase your domain rank as they are practically considered as pages by Google, as explained in their QnA here.

Regarding hosting the PDFs on a subdomain, Google has stated that it's almost the same as having them on a subfolder, but that is highly contested by everyone since it's much harder to rank a subdomain than a subfolder.

Regarding the canonical tags, they are created for "Similar or Duplicate Pages", so the content doesn't have to be identical, and you'll be good so long as most of the content is the same. Otherwise, you can safely have them both be and have backlinks linking from the pdf to the main content to transfer "link juice", as they are considered as valid links.

I hope my response was beneficial to you and that the included proof was substantial.

Daniel Rika

Deleting a post on your site should always be your last resort and 301 redirects are used as a way to remediate the damage that the deleted post would make.

Now, what would be appropriate in your case will depend on the type of website and post. If the post is ranked on google and has backlinks, it would be more beneficial to you to keep both the post and the page and to add a link to the page from the post, while keeping differences between both posts content and meta so that they are not marked as duplicate.

Otherwise, if your posts aren't put on a separate directory p.e. "/blog/post-name" and the title is SEO-optimized, you can just add the extra content and convert it to the page while keeping the previous backlinks and content.

If the old post doesn't have any backlinks, does not rank and has a URL that will be different from the page that you are looking to create, then the best solution would be to create a 301 redirect. After creating the redirect, the post will not be accessible by users or crawlers so you can go ahead and delete the old post.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

The Moz spam score is measured on a multitude of metrics, some of which are related to backlinks and some not. The fact that you have purchased an old domain that dates back to 2013 on web archive ( which although in itself is not negative), is possibly a factor that has contributed to tip over some flags.

You can find the full list of metrics that Moz uses to calculate the spam score here:
https://moz.com/help/link-explorer/link-building/spam-score

You will need to analyze the factors listed there in order to work on improving your Moz Spam Score.

On the other hand, the Moz spam score is a metric created by Moz and it doesn't necessarily represent how your site will rank on search engines. I suggest that you keep adding quality unique content and good backlink on your site, and I'm certain that as the time passes your site spam score will decrease.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

To clarify, the site is on google and it does index.

Now as to why the site doesn't rank for the requested keywords, it will depend mainly on the backlink building and keyword optimization. Checking your backlinks on Moz Link Explorer, I see that there are only 6 linking domains.

What you can do is create pages that are optimized to rank for the keywords that you are targeting and start building quality backlinks for those pages, and slowly you will see them grow through the ranks. Once you have more pages that are ranked higher for keywords, your domain authority will grow and it will become easier to rank for new keywords of higher competition.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

Whether you want to index the pdf directly or not will mostly depend on the content of the pdf:

• If you are using the pdf as a way to gather e-mails for your newsletter, or if you are offering the pdf as a way to get users to your site, then it would be best not to have them indexed directly, but instead have the users go to your site first.
• If the pdf in itself is a way for you to promote your website or content then you can index it so that it can be accessed directly and may help you to get a bit more rank or clicks.

If you are looking to track pdf views, there are options to connect GA and track your pdf views, such as this plugin.

If the content is similar to the web page, then you can put a canonical tag to transfer the ranking. You can add it to the http header using the .htaccess file as explained here.

Daniel Rika 

It depends on how it is implemented on your website. If it's just a plain page with a title and description, and just the image slammed into the page with no content, then it won't do any good for page or image SEO. Instead, it can even harm your indexability as the pages might consume some of the "crawl budget". You can read more about it in my answer here.

My suggestion would be to link to the images directly. If you want to however keep the image pages, you can set them not to be indexed through the meta no-index tag in the header. Regarding image SEO I would suggest you work more on optimizing the image file name, title and description on the page where you are using it, and keep creating quality links for your website and pages.

I hope my answer was helpful to you. If I had a link to the website I would be able to give you a more accurate response/solution.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com
info@dalerioconsulting.com

The issue with your slider is that as all 4 slides have the same text which is copy-pasted for every slide, and it might hurt your keyword optimization.

Since your site doesn't have an H1, the ideal solution would be to turn the slider text into an H1 and make it so that the text floats over the slider, and not cycle the same text all over again, or setting an H1 outside the slider.

Alternatively, it that's too complicated, switching the text of one of the slides as an H1 would be a plus for the website.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

The new max-snippet feature is used for you to limit up to which length of characters you want to display the meta description for the page. You should be able to put any positive integer there.

The issue stands by the Meta Description best practices. If your meta description is over 160 characters, then Google will shorten it not to take too much search results space, so ideally you would want to put a max-snippet length of up to 160.

You can find more information about Meta description best practices here.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

If the pdfs are duplicate within your own site, then the best solution would be for you to link to the same document from different sources. Then you can delete the duplicated documents and 301 redirect them to the original.

If the pdfs are duplicate from another site, then disallowing them on robots.txt will stop them from being marked as a duplicate, as the crawler will not be able to access them at all. It will just take some time for them to be updated on google search console.

If however, you want to add canonical tags to the pdf documents (or other non-HTML documents), you can add it to the HTTP header through the .htaccess file. You can find a tutorial on how to do that in this article.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

Hopefully, I understood the question right.

You don't get duplicate content for the product if the product is located on two different pages (categories), as you are just linking from 2 different sources while the content of the product is unique. You do get duplicate content for the category, however, if all the products in both categories are the same, in which case there is no point in having both categories so you just merge them or 301 redirect one of the categories to the other.

You can get duplicate content if there are tags that have the same posts as categories. Many people no-index the tags entirely, but depending on the site you may watch out so that they don't contain the same products(posts), or just 301 redirect from the tag to the category.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com
info@dalerioconsulting.com

The purpose of the <base> tag is to set a base domain for linking to elements within it.

Basically, what the base tag does is if you set your <base href="moz.com"> and you link within the document to "/community/q", then the link will take the user to "moz.com/community/q".

There is no effect in SEO besides the fact that you will be creating backlinks to the base site for each element that is referred directly, without a URL.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

NoFollow links are normal and have been proven to be healthy when it comes to ranking on Google. In fact, if you have an unhealthy ratio of DoFollow vs NoFollow links to your site, it could raise red flags for SEO.

As the NoFollow attribute was introduced in 2005, the entire web slowly began to switch to NoFollow because of fear that they would be penalized by Google if their user-generated content was linking to spam sites. That entirely defeated the purpose of introducing NoFollow in the first place, and because of that Google has recently introduced and has been pushing the use of "sponsored" and "ugc" tags.

In a case study by SemRush, it was noted that for the #1 ranking pages on Google, around 20%-40% of their links were NoFollow. In fact, the percentage of NoFollow links for the #1 ranking page was higher than the percentage of NoFollow links for the entire site.

To sum it up, NoFollow links are good for your site and you should continue building links on quality sites, with a bit less regard to whether they are DoFollow or NoFollow.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com

The main takeaway for me would be not to focus too much on the NoFollow/DoFollow links ratio. If there are listings where you can put your site and you can get traffic and rank from, then just go ahead and add your site there. A site with (no-spam) nofollow links will always rank higher than a site with no links.

Having your site listed in those directories can in fact sometimes give you more credibility or even new leads, and if the directory has a high spam rating, you can always disavow the backlink.

Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com