Is it better to have a lot of backlinks from fewer websites or less backlinks from more websites? Let's say I joined ten forums and had 100 backlinks from each forum. Would Google consider this equal to having 1,000 backlinks from 1,000 directories?
having fewer links from relevant websites is better than having lots of links from irrelevant sites. good luck with your link building.
You want as many unique ip's as possible. More sig links on a forum will bring more traffic since it increases your chances of getting a click.
google bases how important a site is by how many DIFFERENT sites link to it. It's also better if the sites have a higher PR and have been around longer. There are many factors that go into backlinks.
You might have backlinks in thousands of pages in different websites. But Google may count only 10-20 as valid backlinks which affect the pagerank directly. You can check the valid links writing > links:yoursitename.com in Google Search. Try Google Webmaster Tools. It will help you in many ways regarding all these issues.
I tend to think the best links are the ones that are from a site/page that ranks well in the serps, much more important than the PR of the page.
I remembered that it was mentioned on Summit that each website only cast a unique vote towards another site. That means even if you get 1000 inbound links from a single website with a unique IP class, it is always consider as a single vote towards your website.