Google updating of backlinks

How long does it take for Google to update backlinks?

How long does it take on average to get better ranking from added links (whether earned, bought, etc...)?

 

well, it almost immediately... until google cached the page where your link is..

 

Backlink and sites must mature in the eyes of Google, so this answer is incorrect. It can take around 4-6 weeks in my opinion for a backlink to mature and become useful to your site, some weight is added once its cached but should increase as it matures.

 

What are the best and worst types of backlinks one can get? Can a backlink actually hurt you (ie can a competitor do a text link like "paid link" and point to your site and hurt you? Or some anonymous negative postings on the web?) I thought Google said nothing anyone else can do will hurt you, but apparently there are things a competitor can do to hurt you.

 

google mostly updates the backlinks before toolbar pr update

 

Stay away from "bad neighborhoods" and get quality links from relevant sites.

 

Yahoo shows more than 1000 backlink for my site ,on the other side Google shows about 20 backlinks?Why is that so?Does google hide them?

 

you mean to see them with the "link:" command? usually it's more frequent than the PR update, like once every 2 months

a few days I think

 

according to webmaster tools, google is always updating the backlinks, but users don't usually see back link updates until a few weeks before a PR update.

cheers

 

I think Loco.M is correct.
I heared somewhere that but I don't remember it.

 

I see my backlink update 3 time after recent pr update..But no big adjustment..Maybe you can see a big change every pr update..Correct me if wrong..

 

this is the thing only google knows, but generally about the site's rating.