when i use google and search "link:www.mysite.com" and there is no change after i make several linke exchange. it this regular?
Link exchanges are not natural links. You are only getting a link because you gave the other site a link - google devalues or ignores these type of links. Google also only shows a fraction of backlinks they know about.
on top of what the other two have said, Google doesn't show all your links that way as policy, so check what backlinks are 'findable' in yahoo and/or register with Google webmaster tools, where you'll find a more full list of the backlinks google knows about, it only updates periodically though.
thank you "google link: www.mysite.com" is not exact for the number of backlinks. so are the backlinks actually existing but google did't know about is helpful for my PR or other?
Google got tired of other webmasters using the link command to find their competitors backlinks and trying to duplicate them. They only show a fraction, but do count ones that don't show. You can verify your site with google webmaster tools and it will show you all backlinks they know about.
i find "http://siteexplorer.search.yahoo.com/" and it could give me some information of the sites and links, is this exact?
Maybe your link exchange partner doesn't link your site on their page. Or maybe they just removed your site link on their site after linking their site on your site.
I Thinks Google Link:domain name Shows the Quality Links and Also Maybe your Link Partner restricted the Link Page by Robot.txt.
i search my site by http://www.backlinkwatch.com/index.php and http://siteexplorer.search.yahoo.com/ they all told me that i have around 890 backlinks but i use the google webmaster tool it give me 15 backlinks to the folder and 424 backlink to the index page is that said google devalues or ignores another part of the links? ps: i only make 9 link exchange now