SevenCubed - 2:26 am on Jul 2, 2011 (gmt 0)
Based on Tedster's observation of 60 days and mine of 90 days it's probably accurate to guess that it's probably proportional to backlink percentage as a whole. A sliding scale.
I have a client who recently contacted me asking me if I would like to place a link back to my site in the footer their site. It was quite unexpected because I didn't realize they would have an understanding of that. It's a site that I did more than a year ago. They are happy because they even outrank Wikipedia for something he really wanted to be #1 for due to all his hard work he put into it. So I've accepted and will do so sometime soon. It's relatively large site in comparison to the site sizes I usually output.
I'm still trying to decide on what anchor text to use. But more importantly the total backlinks from this one site will almost match my current backlink profile -- it's going to increase it by 100%, all from one site, all same anchor text.
I'll have to remember this thread and comeback and report what happens when I do this -- might be a good study. And again, the backlinks will be of more value to me than the negative backlash from Google.
It seems these days Google wants us to fear building backlinks to make us more dependent on them. I'm going in the opposite direction. It's also worth noting that for the exact same very competitive 3 word term Bing has me on page #1 in position #4. Bing is very good at understanding site-wide focus funneled to a key point naturally without backlinks but they are terrible at long-tail secondary focus.