As the subject states, I have 3 simple questions on backlinks: 1) If I have a chance to get a backlink from a high PR site, should I link to my home page or to my landing page? The landing page is for my first product, but I do plan on releasing other products in the future. 2) Does getting a backlink from a "high PR" site amount to much if the actual page your link is on is a low PR page? 3) If I want to link to the default page in a directory, is it OK to link to the directory or does that inevitably lead to canonical issues? For example, linking to www.domain.com/directory/ instead of www.domain.com/directory/index.htm. Thanks.
1) As you plan to create more pages, then I would suggest to put he link to your homepage and good intra-site linking strategy. 2) Links from (high PR) sites are perceived as authority links, therefore a link from low PR page of a high PR site will have more positive impact on overall SERPS. Anyhow I think that the pure PR depends solely on PR of page. 3) Google used to see "domain.TLD/" and "domain.TLD/index.php" as two different pages. Concentrate all your efforts just on one of this two alternatives. I personally use "domain.TLD/" as you can not link to specific files from some directories (because of forbidden deeplinking) even it is your index page and as well as because it is shorter to write.
Yup, I agree. It's easier to spread the PR from the homepage. I don't know if I totally agree with that. My understanding is that Google works on a page-by-page basis, not a site basis. If Google gives an inner page a lower PR, it's for a reason. I don't have any empirical evidence for this, just my best guess. Yes, make sure you never give the link as "domain/TLD/index.html" and you shouldn't have a problem. if you give out the link with the "index.html" part at the end, people might just chop it off when linking to you and then you end up splitting the authority between two differetn URLs.