Generally, Google updates its algorithms several times a year. There’s no way to know when or why a Google update will happen, so it’s best to adhere to best practice SEO guidelines at all times.

A site with no links to it from outside websites must not be a useful, link-worthy site. Such sites, not surprisingly, tend not to get indexed by Google. If they do get indexed for some reason, they are unlikely to rank in search results.

That’s correct. If you want those pages in Google’s index, then you’ll need to allow Googlebot access to the pages without requiring log-in or cookies. To do this, you’ll need to use the Schema.org paywalled structured data element to ensure that Google parses your paywalled or subscription content correctly.

An image alt tag is the text that appears in a small box when you hover your cursor over an image. Alt tags should convey the key information from the image that the user would not receive if she had image loading turned off or she was visually impaired. Search engines also look at alt […]

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Featured Snippets are the “answer boxes” that appear at the top of the Google results page. You can attempt to rank for Featured Snippets by providing a concise, useful answer to a common query.

Google truncates title tags at around 60 characters, so keep them between 50-60 characters.

Google truncates the meta description at around 160 characters, so optimal length would be 50-160 characters. Include your keyword if you can, but make sure your meta description entices the reader to click on your page.

Don’t bother with meta keywords. They are not a ranking factor and are useless in terms of SEO.

No, there is no harm in letting Googlebot access your JavaScripts.