A reader asks:

In the blog you wrote yesterday (yes I am reading it) on point #3 you said that only the free directory listings help SEO. What makes you say that?

Google has made a huge thing out of not giving PR (page rank) to paid listings of any sort, because it violates their basic concept of reputation if you can buy rank that way.
Any sort of paid directory / ad / listing service is supposed to use tags that tell Google to ignore the pages as a source of Page Rank.
Now someone could ignore that, but at their own peril. Google has a mechanism for people to report on violations. You could then find your rankings drop suddenly.
So paid listings can generate traffic but don’t DEPEND on them for search engine rankings.
That’s the problem with any so-called “black hat” SEO techniques. You can’t depend on them. Whereas “white hat” methods deliver stable rankings not likely to suddenly drop off the map.
There’s a slightly different situation with WIkipedia. It’s Wikipedia’s policy to tag the whole site to not grant Page Rank. That is to keep people from spamming the site to build up their SEO. But that is Wikipedia’s policy, not Google’s. Google’s Matt Cutts has stated that Google wouldn’t be opposed to Wikipedia changing that. So perhaps at some point, Wikipedia articles from certain trusted people will generate PR.
Wikipedia is supposed to be completely non-commercial. You can put up articles about yourself or with links to your website, and those are legitimate, so long as they don’t turn into advertisements. So again, Wikipedia can help generate Internet Presence and traffic, but it is not going to get you search engine rankings.