As a software developer I try to stay informed about a variety of topics. As a web developer specifically I read about online advertising, content management systems, and search engine optimization. SEO is particularly interesting because it's very unique in the way people choose to attack it and this can directly affect a site's programming. On-site SEO can be good, bad, or downright ugly.

The Good
All search engines perform one task. They refer users to the information they're looking for. But each search engine has different methods of performing this task. Some treat the freshest pages as most important while others prefer a long lifespan. Some consider links from anywhere while others ignore spammy links. What they have in common are human users. They're trying to give people what they're looking for. One logical way to do that is to attempt to "read" web sites as a human would while indexing. After all, web pages are generally created for human readers. So what better way for a computer to "understand" what's on the page than read it as a human? Therefore bold text stands out. The first paragraph of an essay usually highlights what the essay is about. Links within the text send readers to other sources of relevant information. Eventually search engine spiders will evaluate phrases for "meaning" and maybe even emotional tone.

So good search engine optimization begins with optimizing a site for readers. Why? Because search engines are attempting to be like readers themselves. Good search engines continually change their algorithms to analyze pages more and more as a person would. Plus they return pages that they compute a human will want to see. It also helps that your visitors will appreciate a site that's easier to read. What's the point in having search engines send people to your site if your visitors will never want to return?

Then there's the information attached to every page which a human will usually not see directly, but is very useful to a computer. A title gives a way to name a page. An EM tag tells a browser and search engine that some words deserve special emphasis. An H1 tag gives a meaningful heading to a section of a page. So good SEO requires proper use of HTML and CSS.

This sort of on-site SEO is great for programmers. It's easiest to explain why with an example. Let's say we're developing a custom classified ads site. We want URLs that are good for SEO, so we use a directory structure of locations and categories such as /new-york/for-sale. Programming for that is easy because we can break a URL into logical components to know what to display. Page structure can also be straightforward to program, with basic navigation links on the top and side, title in an H1 tag, and affiliate links below the body. Hits to our data source will be low because we only retrieve what little we need to display an ad. Let's see what happens when our SEO goes too far.

The Bad
On-site SEO turns bad when focused more on the search engine than the human reader. Page titles can be tweaked so keywords appear earlier and in better order for search engines. But stuffing a title with too many keywords will make it ugly or meaningless to your viewers. Search engines have long been watching for hidden or near-hidden text. Putting a thousand links on one page which no one will ever click on is just asking to be ignored by search engines.

Sure, you can get more hits from search engines with these tactics. But consider the consequences. A search engine which is filled with ugly results will deter users. So if a search engine wants to succeed in the long term it needs to filter these results, or at least send them to the bottom of the results. Therefore keyword stuffing and other similar efforts can only succeed in the short term. Remember, search engines want to send people to sites they'll want to see. So don't go overboard trying to leverage search engine algorithms.

Let's also consider what happens to our classified ads site. We can set words within the body of our ads to bold which we think are keywords. It's not what our poster did and it may not be what our visitors want to see, but it'll help SEO. It's a little work for the programmer and may make the page slower to execute. We can fill the bottom of our pages with links to every other area on our site. Since our site is dynamic we'll have to determine from our data source what every one of those links will be. We can easily double or triple the size of our site's code if we focus very heavily on SEO. This gets us a slower site, more bugs, and possibly unhappy users.

And The Ugly
SEO turns totally ugly when focused only on the search engine. There are sites which just copy Wikipedia articles, change the text a little, and throw up ads hoping to gather some search engine traffic. They'll get a little traffic for now, but eventually all popular search engines will push links to these sites to the back. Plus they'll never get return visitors, which can be a real cash cow.

Let's say our classifieds ads site changes its focus completely to SEO because profits aren't high enough. The body of our ads are now only a tiny fraction of any page, with the rest of the page's real estate filled with links, keywords, and PPC ads. Instead of working on the user experience we're now spending all programming expenses on continually tweaking SEO. As search engines change so must our methods, so the programming work will never end. We're alienating users by continually changing the site with features they won't appreciate. Plus we're probably creating more bugs and slowing down our pages even more. A typical programmer will have more fun improving user experience rather than chasing ever-changing SEO logic. The programmers will also get frustrated with the complicated logic behind duplicate content at various URLs as we try to convince search engines we have more pages than truely exist.

There's collateral damage when on-site SEO goes overboard. A site can not focus on only SEO as a long-term strategy. If you want a well developed site with happy users and happy programmers focus on usability and readability. It's the only way to achieve long term profits.