This page describes the scoring on WeChall.

Currently, each site has a certain score that depends on three factors:

1. The base score for the site.
2. The number of challenges on that site.
3. How well our users do on that site.

Example:
Electrica's base score is 10000 (default value, adjustable by admins).
Because it has 44 challenges a score of 25 * 44 = 1100 is added to that to get to 11100.On average our users have completed 42% on that site.
The score for that site then becomes base+base-avg*base, or
11100 + 11100 - 4662 = 17538 points.
So the harder a site is the more points it generates.

The score of a site determines how much rankpoints for WeChall you get.

Example:
Imagine Peter has got 30000 points on HackQuest, from a maximum of 100000 points.
This means Peter has solved 30% on Hackquest.
This percentage p is adjusted with a formula pow(p,1+100/97) that makes higher percentages relatively worth more than lower percentages. The 100 is an admin-adjustable factor and 97 is the number of challenges on HackQuest.
So on WeChall he gets 9% (pow(30%,2.03)) of the HackQuest sitescore for that.
HackQuest currently has a score of 19698, so Peter gets 1708 rankpoints.

The admins can manually adjust the base score for sites.
It may be possible that a site with less or easier challenges may get a lower score than a site with lots of difficult challs.

Don't hesitate to ask on the forum if any of this is unclear to you.