Not yet, but I'm keeping my eye out. There are a few authors that I wouldn't mind networking with, but they don't seem to take advantage of RG, unfortunately.
> Can you trust people in internet to share your data?
Scooping is a common concern when it comes to posting your preprint or other results. I don't worry about it. RG and other sites, and you should try to keep your stuff posted to a few places for data redundancy, create time stamps, so you can actually show others that you did the work. Article Ten simple rules to consider regarding preprint submission
The ResearchGate platform so far accepts members who have something to offer. From the works presented other scientists can have the benefit of free access. If a cooperation comes out this will be very nice indeed. Generally, do not trust people only through the internet.