Objective: The present study (Shyness 6) compares the benefits and acceptability of two types of guidance on severity of symptoms during Internet treatment for social phobia. Methods: Non-inferiority randomized controlled trial of Internet treatment, supplemented with weekly telephone calls from a technician (computerized cognitive-behavioural treatment (CCBT + Tel), or regular access to a clinician-moderated online discussion forum (CCBT + Forum), was carried out. An intention-to-treat model was used for data analyses. The participants consisted of 82 volunteers with social phobia. The intervention consisted of six lessons of CCBT for social phobia (the Shyness programme) with complex automated reminders. The main outcome measures were the Social Interaction Anxiety Scale and Social Phobia Scale. Results: A total of 79% of CCBT + Tel and 79% of CCBT + Forum group participants completed all six lessons. Large mean within-groups effect sizes (Cohen's d) for the two social phobia measures were found for the CCBT + Tel and CCBT + Forum groups (1.31 and 1.54, respectively). Each participant in the CCBT + Tel group received a mean total of 38 min of technician time over the 8 week programme, while participants in the CCBT + Forum group received a mean total of 37 min of clinician time. Quantitative and qualitative data indicate that both the CCBT + Tel and CCBT + Forum procedures were equally and highly acceptable to participants. Conclusions: The Shyness programme with either telephone support or access to a clinician-moderated online forum resulted in good clinical outcomes with equivalent patient acceptability. These results confirm that people with social phobia may significantly benefit from a highly structured education programme administered by clinical or non-clinical staff.