ResearchGate is a social networking site for scientists and researchers[3] to share papers, ask and answer questions, and find collaborators.[4]According to a study by Nature and an article in Times Higher Education, it is the largest academic social network in terms of active users,[6]although other services have more registered users and more recent data suggests that almost as many academics have Google Scholar profiles

https://en.wikipedia.org/wiki/ResearchGate

ResearchGate is a social networking site for scientists and researchers[3] to share papers, ask and answer questions, and find collaborators.[4]According to a study by Nature and an article in Times Higher Education, it is the largest academic social network in terms of active users,[6]although other services have more registered users and more recent data suggests that almost as many academics have Google Scholar profiles

https://en.wikipedia.org/wiki/ResearchGate

Because every one a scientist here so easy to find related things .

Dear Prof. Mohamed G. E. Gadallah

Thanks a lot,

These are good reasons but not main reason.

I think main reason or one of main reasons is RG-score.

Regards.