The second phase of website development comes a couple months or more after the release of a website. Its called "Search Engine Optimization", which refers to the process of improving the visibility of your site in search engine results. It is important to keep in mind that search engines only know about your site from what words they can find on it. This means that accurately and extensively describing what you do is crucial to showing up in search engine results.
There's a lot more to SEO than keywords though, now SEO involves leveraging websites other than your own to create publicity for your site. Directories such as Google+ (Maps), Manta, Yelp, Citysearch, Yahoo Local, and many others may already have a listing for your company on their online directory, but the next step is to make sure that content is complete, up-to-date, and includes your website address. Most business also leverage social media, such as Facebook, Twitter, LinkedIn, and more.
I link to think that creating a website is like writing a book and self publishing it yourself. Once the book is published and you have an ISBN number and everything, still know one will even know about it except people you have told. The next challenge is to publicize your book (or website) and get your publication connected with people who will want to read it. This is why I consider website development a separate phase and process than Search Engine Optimization.