Matt Cutts recommended in a video in 2013 to add rel="nofollow" on widget links that link back to your website.
Some background of my company: We're a software company for website chat. There's a 'powered by' link in our widgets that links back from our users' websites to our website. Currently these are all follow links.
I checked out the links of our competitors, and it seems none of them have no follow on their widget backlinks. This, together with the fact that the video is quite old and information on this issue rather scarce, makes me doubt whether we should change our widget backlinks to no follow.
Does anyone have thoughts on this?