How much time does it take for google to recognize/calculate/findout backlinks. I am asking this because i just got a backlinks from a pr5. Thanks
it's only Google knows but you can find out does google counted that site as your site back link or not using your Google webmaster tool.
it depends on how frequently google crawl that website where you place your backlink. if that web site is going to be crawled within next 1 week then you might get the back link that time. it's a luck actually. once i got a backlink showed in google within one day!!!
The tim is depend, can be one day up to few month. However, the hgher PR website can be catched faster compare to lower PR website.
DP is getting worse each day. Where did you get that number? Indexing depends solely on the google bot. You link may get indexed as quickly as in 1 minute and on the other hand it may never be indexed. If that's the case build some backlinks to that exact URL that is linking to you and ping it. You may also want to do this if you want the url where your link appears to be indexed as quickly as possible.
Probably way faster for new sites, I registered a name some time ago, made a simple site, submitted to Digg and it got indexed like in about an hour or so. Hope that helps.
I think only search engines know when they will visit that site and from when they consider this link or even they can not consider that link as a valid backlink.
Google uses several factors to assess where your site belongs in the search engines results page (SERP). Google does this by using internal and external factors that surround your website. Internal factors are factors such as new content, outgoing links, header tags, and so forth. External factors is basically the number of back links, which is the number of other websites linking back to your page. In order to rank high on search engines, like Google, it is important to continuously update your website daily and the rest of the battle involves link building. Good luck.