An oft-overlooked aspect of search engine optimization is assessing the broader characteristics of the domain itself. A search engine’s purpose (you’ll hear us saying this next bit a lot) is to automate the business of determining website quality. It’s half of their battle. The other half is determining topicality, but that’s another post.

Pages Crawled (Domain Size)

Size matters to search engines. Big, original-content-rich sites get crawled more often and are more likely to rank well for their targeted terms. A larger site that has a lot of original content is going to be more important in the eyes of a search engine for obvious reasons. Search engines are traffickers of information. The more you have, the more valuable you are. This is provided they can’t get it any where else. Remember that original content is key. Aggregated or scraped junk can actually be somewhat detrimental, search engines hate that: you’re adding noise while they’re trying to boost the signal. (Don’t panic about hosting a feed or two, I’m talking about site clones or even whole site network clones that end up getting the SE smack down.)

Domain Age

Older websites tend to rank better – search engines infer quality by assuming a higher level of investment in aged content. Moving slow and respecting elder sites allows the search engines to partially eliminate flashes in the pan and black hat SEO’s from trying to game the system with the latest unclosed loop holes in the formulas that determine the layout of search engine results pages (SERPs). An older website, espacially one that’s remained active, is the mark of a webmaster committed to their content. So, in short, an older domain scores some points with the engines.

Internal Links Per Page

This is a fairly tame issue, but can shove it’s way to prominence if abused. Your internal link to page ratio should ideally be somewhere near 1/1. If you have an 8 page site and 300 internal links per page, something goofy is going on. (An example of “something googfy” would be internal keyword spamming – posting tons of keyword rich links, usually not user-visible, from each page to the next. An old SEO trick that was short-lived)

External Links Per Page

A site that links out a lot is usually good for search engine marketing. Most webmasters pay attention to their incoming links and will follow traffic back to its source. This can result in a reciprocal link or at the very least another user. It’s a good to idea to watch who you link to though. Lay down with dogs and you’ll get up with fleas. Linking to malware, phisheries or link farms is a good way to see you SERP rank drop.

Another reason we look at this metric is user experience. In terms of SEM and SEO, it’s also a usability thing. (In general a massive amount of external links per page is not going to make for good user experience. It’s overwhleming and they’ll just back out.) Good user experience leads to more incoming links.

Summing Up…

Overall, domain factors usually aren’t a huge deal. Like most search engine optimization areas, deficiencies here can be overcome with a glut of high quality incoming links. Having said that, these factors are often low-hanging fruit for search engine optimizers looking for little edges in the online battle for attention.