Stack Exchange websites, such as Mi Yodeya, include a "voting" feature. They let me click an "up arrow" icon to indicate that a post is useful, or a "down arrow" icon to indicate that it's not useful.
But voting requires a mouse click.
I suspect that clicking a mouse may be melacha. And so, like most types of melacha, I suspect that it is sometimes allowed, but sometimes forbidden, during Chol Hamoed.
May I freely upvote and downvote Stack Exchange posts during Chol Hamoed?