In this paper we introduce an automated assessment service for online learning support in the context of communities of learners. The goal is to introduce automatic tools to support the task of assessing massive number of students as needed in Massive Open Online Courses (MOOC). The final assessments are a combination of tutor's assessment and peer assessment. We build a trust graph over the referees and use it to compute weights for the assesments aggregations. The model proposed intends to be a support for intelligent online learning applications that encourage student's interactions within communities of learners and benefits from their feedback to build trust measures and provide automatic marks.