Findability is one of the most important things when it comes to blogs. With blogging for the web, if you're not found, then you might as well stop writing unless you're writing for yourself. With being found, the higher up you are on search engines like Google, the better you are. Fortunately things like keywords, linking, and archiving by topic can really help with that when done properly.
Most blogs are set up to be alerted if they are linked to. If you link to their related articles of interest, they automatically link to you in the comment showing who linked and where. If you take a look at the comments section of this article on Tutorial Blog for example, you will see an example of trackbacks on the bottom. The more links you get, the more people come. The more people, the higher your stats, and the better you do.
Keywords help by reaping in search referrals. As you write, the more often a word appears, the more you may appear to be an "expert" of sorts for that topic. When people search for certain keywords, if it appears more on your site, you'll have a better chance of being found easier as you'll appear higher up in the ranks. When you archive your posts by topic, you increase your keywords as well as help people get around easier, making it a multi-purpose technique for organization. Any way you can fit a relevant word onto a site, whether it be by an image tag or organization technique, it all helps. For help in coming up with keywords, one could always refer to different keyword tools, or research what the relevant market is looking for.