Like Emily, I dont know that much about SEO, but I'm sure I read somewhere that one of the reasons blogs are picked up so well by Google is because it likes new things, and a blog tends to be updated more regularly than a website text.
Broadly speaking (though most of what I am writing here is a dramatic simplification of something that is actually rather mystical and immensely complicated) Google analyses web pages based on prominent keywords anywhere in the webpage text or header. If you write a webpage about donkey farming, titled "why donkeys make good farm animals", it is conceivable that your webpage will come up when searched for with any of those words. Words like "good" obviously are likely to be found on far more pages and so it is unlikely you will get a good ranking. However if someone searches for "donkey farming", statistically there will be less pages containing both those words. Ok, pretty elementary stuff.
Back in the old days, websites used to try to manipulate search engines by using 'portal pages' - nonsense pages which linked to their websites, containing content designed specifically to manipulate search algorithms. Often simply pages containing thousands of completely unrelated keywords, giving the page the chance to come up in as many different searches as possible.
This doesn't work with Google because:
- Google likes REAL content. They will spot attempts to manipulate the search algorithms and black list sites accordingly.
- Google ranks pages based on links as well as keyword content. If Madame Felicitas, the web-mistress of Felicitas-sextoys.com, decided she wanted to tell her customers about a really good <link>donkey farming</link> site, then your site will start to rank above those sites that have no links to them at all.
This is still pretty elementary. What I wanted to get to was the following: Google doesn't index websites, it indexes
individual pages. The more individual pages with
unique, original content on your website the more "donkey farming" coloured marbles are thrown into Google's proverbial basket. Because most good blogging platforms give each post it's own individual page (usually linked to from the post title) every time you write a post on your blog, you are increasing the statistical probability that someone will stumble upon your website. This is why a page from Wikipedia will so often be present in search listings. Everyone links to it, and there is literally millions upon millions of pages all of which are in the Google index.
A further point I wanted to add while I was on the subject of SEO is that if you are linking using people's banner ads and you aren't using wordpress, make sure to fill the 'alt' attribute with a few keywords in the HTML <img> tag (Google it if you are not sure) as this will help to improve the search rankings of the target site.
Oh PS - Wordpress is awesome!