There is a general rule that larger sites outrank smaller sites in search engine results. Consider the collective effect of a large website: larger sites cover more topic areas, and therefore more keywords and garner broader traffic. The broader traffic yields larger numbers of inbound links from broader classes of other websites. In turn, the site earns trust with search engines more quickly. Meanwhile, each individual page within a site generates a small thimble of PageRank that can ultimately contribute to the overall site PageRank. The collective effect of a large website can bring tremendous ranking power.
The power of this simple device is available to everyone. You need not be an expert at SEO—you simply need to start writing.
As a webmaster, you should always aspire to create a site that covers broad topic areas. That does not mean have a blog about soccer, baseball, guitar greats, and web design all jumbled together. It means that if your blog is about web design you would have a range of topics discussed within that discipline, such as sound coding practices, logo design, navigation tools, and web design trends. To a small business owner employing WordPress as a Content Management System (CMS), that means building a page for each city in which you offer services as well as offering free tips and tools within the WordPress blog section.
In my web design and SEO business, I employ WordPress as both a CMS and a blogging platform. I maintain pages for the main areas of interest to potential clients: one page each for my service offerings (the pages are intentionally separated for ranking purposes: SEO, web design, WordPress development, social media marketing, call tracking, PPC management, and more), a page for a design gallery, a page for SEO case studies, a page for testimonials, and some service and contact pages. However, I utilize WordPress' blogging functionality to write (hopefully) helpful and valuable tips on SEO, such as How Does Google Local Order Its Search Results, and Top Android Apps for SEO. Each month, I take the time to write about three or four such posts. My site ranks highly, but more important to me is the high number of search phrases for which my site ranks.
Anyone can rank for one search phrase. The truly exceptional sites, however, are the sites that have broadness—the sites that rank for wider classes of keywords.
When your site has broadness, other benefits follow. First, you'll garner greater numbers of inbound links—and you'll earn them from a greater variety of sources more quickly than you normally would. Say you've are a web designer and you write a blog post about an innovative CSS trick that you invented. Your blog post will be of interest to other web designers and bloggers. With WordPress' innate tagging functionality, your post will be easy for other webmasters to find. Those other bloggers and designers might mention your post on their site with a link back to you. Congratulations, you just earned a link to an interior page (links to interior pages are usually harder to get than links to your front page) from a website within the same niche as you (links from same niche sites carry more power). You just earned a link that you otherwise would not have had.
Consider also the PageRank effect of that single page. PageRank is part of Google's search algorithm; Google assigns a numerical value to each indexed page on the Web. When an indexed page hyperlinks to another page on the Web (including your own pages), a portion of that numerical value is passed from the linking page to the target page, thereby increasing the target page's PageRank. Inbound links increase your PageRank and in turn, your search rankings. The amount of PageRank generated by a single page is admittedly slight—but it adds up quickly.
One of WordPress' most singular advantages as a search-friendly platform is that it offers simple and speedy publishing of new content. If you have 15 minutes and a good idea, you can create a decent page of new content. If you have 3 hours and a great idea, you can create a great page of new content.