Method to scrape targeted emails

What's up guys?

First of all, I'm not really in email marketing and don't do this, and maybe this method is already used, but anyways... Today while browsing youtube an idea came to my mind.

There are lots of videos on youtube about any niche, any keyword. And there are shitload of comments on each video. Almost 90% of people on youtube use their usernames as email usernames. If someone has good skills in coding, you may code a software which will scrape all usernames on video about some keyword, then add @gmail.com @yahoo.com @live.com to those usernames and validate them. And you'll have keyword targeted email lists.

Hope this helps someone

Haa cool thought. I bet someone with ubot experience could do something with this.