just a simple and short question to ask here... do building inner page backlink help main page to rank in SERP? i have 200+backlink for main page and inner page just like 2~5backlink...
Internal links do help quite a bit. Just don't overdo it with 200 and make sure not to use the same anchor text.
Every page on your site should be targeting a different keyword phrase (possibly 2-3 phrases IF the phrases are VERY similar). You can get as many links to as many different pages on your site as you would like, but ideally the link text pointing to each page will contain the targeted keyword phrase (or slight variations of that phrase) from the <title> of the page being linked to. It doesn't affect you negatively if your inner pages have more links than your main page. In fact, it's quite the contrary. Sites with lots of links to lots of inner pages are seen as more of an authority than sites with most of their links pointing to their home page. So inbound links to inner pages build domain authority. Inbound links to inner pages only help the home page rank for its targeted keywords to the extent that the additional PageRank passed from the inner pages to the home page helps the home page to rank (which is likely not much since PageRank is such a minor ranking factor these days in Google's algorithm and has almost no affect on how a page ranks for a particular keyword phrase).
I agree I alway try to target circa 3 interelated search phrases on the same subject on each page. I also agree on the PR thing. I don't even worry about PR and concentrate on getting pages ranked highly as organic SERPS for being relevant and what is most likely in mind for a particular search term. And OP yes differ the anchor text links when you can (other than the odd duplication) every where outside your main horizontal and vertical navigation structures
Canonical said it already - it is best that every page of y our site, target a particular keyword phrase and stick to it so it is but natural that you will get more links to internal pages with that specific keyword phrase or its LSI variations. It is good actually, visitors will land on your juicy internal pages first with lots of details about the product or service you are offering and then there is high possibility of them clicking on your home page link. It is not expected for visitors to always land on the home page, spread out into internal page landing also.
yes its useful but not more.. I see this a lot.....well actually when i first started learning SEO many moons ago i did it too, I built masses of links going to the domain and neglected the inner pages, although i didn't do to bad for long tail keywords a well SEO's site will have good inner page links too, not just the homepage
Back link to inner pages called deep linking and its help alot in serp . But i think if you have a proper navigation to sub pages from home with proper anchor text then only getting back links for main page will help you alot . In some cases if your website is huge then its impossible to put all sub pages links on main then you can divide them and linking them in a fashion that they bind each other . You may also build a sitemap for larger website with max 20 link a page and divide them to several pages . Wish you good luck