If you needed to hire a new manager for your office you would let people know about the opening by advertising. An ad in the paper would include the positions’ title, job description, and how to contact you. It might also state how not to contact you (i.e., no phone calls).
Meta data and other codes provide similar information to robots including titles, descriptions, and instructions on how and what to read on a webpage.
A robot is what search engines (and other information gathering companies) use to find your site, analyze it, and then decide what to do with it (ignore it, ban it, or index it).
Think of SEO as advertising your site to search engines. If robots do not know about you, like what they see, or cannot understand what you are saying, you will not get search engine “air time.”
Robots – They help.
The Internet search engine process is not run by people. It is run by robots (spiders, webcrawlers, worms, and webants) that (hopefully) visit your site and try to understand and index it. If your site is not indexed, it will not show up in search engines. Period.
A site with good SEO attracts robots and provides instructions, descriptions, and content that robots can understand, analyze, and assign relevance to. A site with no, or poor SEO will either get ignored, or worse – tagged as spam or blacklisted.