in terms of linkjuice/pr when you comment ona blog with 100 internal links and 20 external links and there are say 15 followed external. Is the websites "vote" divided by 1) 15 2) 20 3) 115 4) 120 I also have another question, do blogs really have to be relevant and if so how relevant do they have to be e.g. is posting on a gadget blog page enough or does it have to be specific to the gadget your advertising e.g. no use posting about a nexus one for an iPhone
120, regardless now many are no followed, no follow does not pass link juice but is still considered in the pages passing ability, i.e PR -15% divided by number of links on page. The more targeted a page is, the better. Ideally you want links from pages, which have your targeted keyword included in the link to them. All that being said, you will never optimise for even a vaguely competitive keyword using blog comments!
Yeah I've decided my main target should be article marketing, I understand what your saying as most blogs have over 100 links on them anyway but blog comments can be helpful too, right? If i post say 20 a day? And what do you think about the reevancy question?
you are far better off going out and creating a free blog on wordpress.com or posterous and then writing your own short blog articles and posting them with a couple of links back to your target site than to waste time posting 20-30 comments on unrelated blogs. you can grab articles off of the article directories and just spin them a little, post them on your new free blog that you created and put as many links pointing to your target site in each post as you please.
free blogs are available on: wordpress.com posterous.com blogetery.com blog.com weblog.com metroblog.com xanga.com weebly.com just to name a few
Relevancy is a bit of a grey area, there is little doubt that relevancy is important, but to contradict that, you just have to look at all the top web design companies, they are top of google with nothing but footer links on customer sites (so will be unrelated anyway) and it gets them to the top of the SERP's. Blog comments can have their uses, I often use high authority no follow blogs, so they show up in my link profile, but this is just because it makes it difficult for competitors to analyse by back link profile. Just make sure you use your keywords in the links whenever possible.
I don't think anyone really knows the answer to this question. Unless I am wrong, most people are just speculating. This is one of those Google mysteries
You're also not taking into consideration the value of each of those links. Links in content are treated differently than links in comments, links in sidebars, and links in footers.
Nobody could tell you what's involved in the calculations for the algorithm no, but many of us do test these theorys, so we can developed an informed opinion on specific elements of it.
i also do agree with you. If one set of result works for one website it is not mandatory that it will work others. And while concluding comments over Google issues we can only predict on the basis of our experience but we can't say, yes! this is it.