Award userpoints for each share

i agree... need to have a trackback system or something that check the presence of the content shared, otherwise is useless... :)

Yes but we can implement referrer.

I have the following scenario in mind:
A user click share on a page like this:
http://example.com/node/123

and I want the service link url to be:
http://example.com/referrer/[ref_code]/node/123

The referral function will redirect after referrer cookie is set to:
http://example.com/node/123

I replaced the original function of referral_get() using hook_menu_alter, with the following:

function referral_mcs_get() {
  global $user;
  
  $args = func_get_args();
  $referral = array_shift($args);
  $path = implode('/',$args);
  
  if (!$user->uid) {
    // User has not logged in, or registered yet
    $uid = _referral_ref2uid($referral);
    if (($uid) && is_numeric($uid)) {
      // Set the referral cookie
      referral_set_cookie($uid);
    }
    if(drupal_valid_path(drupal_get_normal_path($path)) ) {
      drupal_goto($path);
    }
    else {
      drupal_goto(variable_get(REFERRAL_GOTO_PATH, 'user/register'));
    }
  }
  drupal_goto();
}

Is working fine, is redirecting to any page after referrer cookie is set and if last args are valid internal or alias drupal path but I can't alter url of service links to use this functionality.

Is there a way to alter url's of service links?

Temporaly I solved by appending a custom param ref=true to end of url and then modify that url using hook_outbound_alter() where the ref is set to true. But is not an elegant way...

hook_service_links_alter() works as all the alter functions... if you look the service_links_get_links() you may have more details about params.

I saw the hook_service_links_alter() but we get a static 'link' key and we need to prepend to the service links url the referral link url wich is dynamic... I don't see a way to modify the service links url with dynamic content using hook_service_links_alter unless we rewrite a big part of service_links.module in our own module.

maybe i didnt got the point but you could add a callback function to every service and save the callback if already present in another field, then the link and settings will be elaborated by your function...

This solution is a little tricky but SL 2.x has been built over the old 1.x which was quite simple, that's why i wish rewrite the third version almost from zero starting with another perspective: #1353802: Service Links 3.x plan