devu

This plugin / widget substitutes the default “Links” widget. If you are a SEO specialist, you already know how much important is the rel=”nofollow” attribute in outgoing links. If you are not: links passes part of the PageRank the page has gained to their destinations. Do not let the blogroll section wasting it by donating your pagerank to external sites.
Once installed, under “Settings” -> “SEO Blogroll” you can create how many link boxes you like, each with its own title. Every link box can contain how many links you like. For each link, you can decide if it should have the nofollow attribute or not.
Once your links are ready disable the traditional “Links” widget in “Appearace” -> “Widgets” and activate the new SEO Blogroll.
If your theme supports widgets, you don’t need to change a single line of code, just install the plugin and start using it!
Please report any bug (or enhancements requests) on the plugin main page: <a href="http://www.francesco-castaldo.com/plugins-and-widgets/seo-blogroll/" title="Seo Blogroll" rel="nofollow ugc">Seo Blogroll</a>.
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More information: http://www.francesco-castaldo.com/plugins-and-widgets/seo-blogroll/

SEO Blogroll

Lets you decide which blogroll links have the nofollow attribute. Don't waste link juice!

flocsy

SEO Tag Cloud Widget displays the tag cloud in a SEO-friendly way, using a search engine optimized html markup. 
It looks the same as the default WordPress Cloud Tag, but with an optimized html markup. 
You can put it to your sidemenu.

SEO Tag Cloud Widget

SEO Tag Cloud Widget displays the tag cloud in a SEO-friendly way, using a search engine optimized html markup.

SEO Blogroll vs SEO Tag Cloud Widget