Link building question

I have a ecommerce site and a blog on the same domain but on a subdomain. for example my ecommerce site is located on the www domain for example www.mydomain and My blog is located at on a subdomain at site.mydomain. Now if I have a outside website link to my blog at site.mydomain will help my SERP for my ecommerce products at the www domain the same as if it pointed directly to the www domain? If you know what I mean? Thanks!

A link straight to the page that you want to promote is most effective. However, that assumes that the topic of the linking website is the same as the page that receives the link.

oh ok, but it will still help on some level correct?

Now that is an interesting point... If the goal is to increase on SERPs for ones targetted search terms.. Will what you a doing help? I would guess that the search terms would have to be extremly uncompetative for this action to move your site up in the SERPs. It reminds me of the peeing on a forest fire analogy.... It still helps on some level......

Link swap with other sites will help

If u place web site link on blog and blogs link on web site.It will really help.

links in signatures on forums help as well as link exchange with related sites

ok but my main question is. if I have a blog on a subdomain and have another site link to that subdomain will that help my SERPs for keyword and products that I sell on my main domain?

I already know about how linking works in regards to my main domain. but I am asking if the link is pointed to my subdomain will that help me as much as if it was linked to my main domain? my whole point of this is since I am having a hard time exchanging links with my main domain because other sites want too much money for basic links since they see I am a retail store I wanted to create a blog on a subdomain and ask them to link to my blog (on the subdomain)

It will help. You can make it help more by manipulating relevance and anchor texts. If the link comes into a themed relevant page and you use relevant anchor texts to link back to the home page (or other internal pages) this will help. Google now treats subdomains as part of the same site.