Don't use auto approving blogs. THey will not be good comments nor will they be considered as a good backlinkg. Infact it will probably hurt your SEO
Today it is all about Google safe. I've seen a lot of people are intrigued with the promising services like "100000 auto approve comment blog", "thousands wiki links", "thousands social bookmark service", "thousands and thousands promising back links services that will hurt the site. that's full of crap. It is always wise to keep everything natural and fair. If we want to have decent position in Search Engine, we must respect the rule and not try to brute force such blind massive links that are not safe for our site.
I would still say blog commenting does add value BUT auto approved blog comment pages ARE for sure dangerous to SEO. Because, eventually the auto approved blog comment page will become an outbount linking spam page and a link from a crappy page will be a -ve seo value. So dont go for auto approved, do a scrapebox, find good quality related blogs and make genuine and relevant comments, join the conversation and contribute to get the credit for a backlink..
These sites are showing as Parked domains. At the very lowest line there is a sentence saying "This domain may be for sale".