Help seeking is regarded as an important learning strategy that reflects students' metacognitive and domainspecific skills and knowledge. This study developed a proactive online discussion forum that strengthens social networks in an online discussion forum to facilitate help seeking for problem solving. This forum allowed students to proactively invite friends or potential experts to participate in problem solving. A quasiexperimental approach was conducted with a sample of 37 students. The students' behaviors of problem solving, ego network patterns of problem solving, and perceptions of help seeking were addressed as dependent variables to assess the effect of the proactive online discussion forum. The analysis results revealed that the students in the experimental group exhibited more frequent participation in problem solving, and showed more positive attitudes towards help seeking. The results also indicated that the experimental group demonstrated more in-depth participation patterns of ego networks. The findings provide some evidence for the effectiveness of the proactive online discussion forum in terms of promoting students' participation in problem solving and their attitudes towards help seeking.