Some SEO Internet Marketing questions...?

[Jake]

A general SEO rule, the easier a link is to get, the less value it will tend to have, those auto approve blogs get over-run by spam bots, so tour comment ends up sharing link juice with perhaps 500 other links. Spam is probably as big an issue as the fact that the seo benifit is devided amoung the links, diluting it on pages with lots of coments.
Wordpress by default gives noFollow comment links, choosing the moderate setting makes comments on your site not auto approve, Akismet is one of the better spam filters that reduces the number of posts you must review.
I would use social media plugins for just a couple of sites, dozens of badges tends to get less bookmarks.

I don't understand where you would: "type in either the 'do follow' or 'no follow' code"
While noFollow provide limited ranking benifit, you need a fair percentage of them in order to avoid an unnatural link pattern, some say noFollow still helps the site authority a bit.

Here's a backlink searching tool that helps create search queries that get the most useful results.
http://dropmylink.com/