Many businesses wonder, what is the purpose of having a blog? Depending on your stance and marketing objective, blogs (short for web logs) are great open source tools (known as content management systems) that if wielded properly can be instrumental to SEO and organic search engine positioning.
Blogs implement topical pooling of link flow through using a platform of internal linking that makes it crystal clear to search engines what each sub folder is about.
Keep in mind that most sub folders are still viewed by search engines as entirely different sites, so through strategically cross-linking pages or posts from one sub folder to another, the synergy it creates can create spikes of link flow which translate into rankings.
Another great advantage blogs offer to static or legacy (CMS) content management systems that lack SEO prowess is, the ability to ping and promote its own content through RSS feeds and send search engine spiders deeper into a site.
The logic is simple, if you create a relevant page with a specific ranking objective (such as creating another layer to secure a competitive series of keywords, a hub page or a landing page), you can sculpt which page gets the most link weight from other pages based on site architecture and internal linking.
Blogs take the content and make it accessible instantly to search engines and puts your page in the Que for crawling from using RSS feeds. Once the bots arrive, if you have any links on the page, they follow and ping those links as well (which in turn schedule them for crawling).
This chain reaction can bring pages that have tapered off and fallen to less than favorable positions due to neglect or lack of revision or links. Blogs ensure that (a) more link flow is captured from the RSS and activity from syndication as well as (b) that the pages linked to from it have a new opportunity to make a second impression for search engine relevance.
Once a page is in the search engines’ index, it can start aging and maturing. Based on how it is linked to, the value of the content in context to other related information on your site and the authority it creates over time internally, each page is an asset to be eventually leveraged for SERP domination.
Out of site, out of mind applies for search engine spiders. If your content was fresh (way back in 2007) and you really haven’t done anything to stand out or target any additional phrases, then you give them no reason to return to pay attention to your website.
With the constant pressure of competition vying for coveted market share (which is divisible by rankings earmarked by keywords), your pages are either a relevant result or they are not. Part of that relevance is determined by post frequency (how often your site contributes new pages or revises older content). Also, how you link to yourself (with relevant keywords) and how others link to you.
Without a solid foundation any links you acquire from other websites only have a limited shelf life. If your pages have a solid site architecture (like a blog) can move that link flow around within the site to the pages that need it most, the potency of each link can be sustained further with less effort.
Two things to consider the waning factor and the tendency for information to get archived in blogs, both can create drops in position. The remedy to this is deep linking (linking to other pages other than the homepage) with specific anchor text, continuity and volume from other areas of the site.
For example, if I have a page tucked away deep in the site (3 sub folders away from the root folder) and I am expecting to drive traffic there and have that page rank well in search engines, the fact that it is so far away from the primary navigation presents a challenge.
Think of it as a pyramid of glasses and pouring champagne in the top glass and having the spillover funnel down from glass to glass so that even the glasses on the bottom are full.
Link flow works in this manor. However, in this application, links are the fluid moving from one vessel (page) to another and if they have more than 50% fluid, then they can garner rankings in search engines (since they now have passed the threshold of internal relevance).
The point being, before you can acquire rankings, your pages need to be indexed. The more pages you have indexed on a topic, the better. Even more important, the number of pages internally linked on a topic, the easier it becomes to have the aggregate collective coherence of those pages appear for multiple keywords.
Pages with stronger internal links require less external links to rank higher. So, to answer the original question posed at the beginning of this post, the purpose of having a blog is to develop an authority website.
By reinforcing your topic (theming and siloing), your site is deemed an authority (which is the real reason to start a blog), in addition to the ease of posting updates or new content.
The short-term benefits will be obvious, the ability to create spikes in rankings for keywords in the titles and topics of the post. The long-term benefits are immeasurable as your site gains more momentum and becomes a market share devouring ranking juggernaut if managed with purpose.