Hi,
As long as you don't join a link directory, get listed on adult sites, or blacklisted site...or something like that linking will not hurt you. Remember Google does NOT see a website....they see web pages.
So having all inbound links going to your home page will help (1) the keywords you optimizing your home page for (2) increase the link value of your home page. Increasing the link value of your home page means internal links coming from your home page will also be more important.
BUT...if you have all your links going to your home page and non to internal pages that will not help your internal pages. So YES, you want to build links to your home page...like "Inventube" "Inventions" "Inventors" "Invention Community" and those big keywords.
But you also want to build links like "
Invention Forum" to your invention forum...which by the way you need to log into your Vbulletin and change your meta tags for the home page...I think it is
Admin CP -> vBulletin Options -> General Settings -> Meta Keywords
P.S. don't start building link for DEEP internal page yet....like for: Inventube Resource Center - Young Inventors
because we will installing the SEF URL mod eventually which will change that URL. We could just set up 301 Re-directs for each page but that will get too messy. So build links for the home page & your main categories (those will stay the same) just not your deep internal pages yet.
Jeff