If your a blogger starting out, or maybe have several blogs, or your just deciding which widgets to use in your new Wordpress blog, a few tips can help you out. Knowing how the search engines work can greatly improve your success. If a search engine comes across duplicate content while searching your links on your site, this will give each link less "link juice" as the experts call it. Why? because it is indexing the same content twice.
So, if you are using a tag cloud, and each tag only refers to 1 article, then the content will be counted multiple times. Removing the Tag Cloud could greatly improve your SE scores, as each post content will only be indexed possibly three times (once on the main page till it falls off, once on a category page, and once for the post's page). This is a good reason to make sure you post often, so that articles never stay on the front page for too long. Include an "Archives" link so that the SE can find the older posts.
If your blogging about a single topic, rather than a couple, it may even be a good idea to remove the Category menus. This will again reduce the number of times the content is "seen". If you do use categories, be sure the category is in the Title of the page first, and in the description meta tag. The description tag should be unique to this category.
Once you have hundreds of posts on the same topics and tags, you may be able to re-introduce the tag-cloud if the number of tags is small. Overall it helps if each blog is concentrating on a small topic as this will reduce the categories, and tags. Never place a post in more than one category.