I'm not really up to speed with YouTube and its rules and trends, I just post videos that I found interesting or some that I filmed myself every now and then. But searching today I saw some uploads that looked like they would be of interest only to see that they were all my videos and in one I even appeared. Someone has made their channel with only my content but with modified thumbnails!

Is this a 'thing' where you just use other people's videos to make your own channel content? I thought about complaining but is this a valid grumble or should I just let it slide?

It's a valid grumble if it's your original work, and I think youtube will delete it if you complain.

Yes, it's a valid grumble!

Before reporting them, you might want to just check and see whether they've credited you at any point, anywhere on their channel. If they have, that might signal that they are simply fans of whatever it is you do. That doesn't mean it's all right for them to re-upload your work, but at least then you know that their intention isn't bad.

HOWEVER, if they have given you no mention whatsoever, and are trying to pass it off as their own work, then absolutely report them to YouTube. By giving you no mention, they would be allowing viewers to believe it's their work as opposed to your own. Which isn't something you should put up with. In these circumstances, report them.

youtube must have a full time team of people deleting copyright infringing material, I quite often see entire TV shows/ training courses posted for a few days.

Thanks. Some of the content is 100% my own, some rescued from old home recorded VHS tapes. No, I am not mentioned anywhere they just copied and pasted everything but used a different description and thumbnail. I'll report to YouTube and see what happens.

When you say "home recorded VHS" do you mean broadcast TV? If the content is video you have filmed yourself with your own camera then you totally have a case, as you own the copyright. Anything you recorded off the TV, found online etc is not the same. They are only doing the exact same thing you did, find stuff and repost it.

It depends if the OP has added voice over work and graphics to his content that they have pinched as well. If they have youtube will pull the other peoples videos. If however it is just scenes from broadcast TV then the OP doesnt have the right to purse a copyright infringement as he is not the content rights holder, that would be whoever owns the copyright to the show.

Isnt that what cwilliams1976 used to do?

As some others have mentioned, you don't have to own the original copyright for Youtube to take action. If you have spent time and effort 'rescuing' old content for posterity - and the other person has just copied your work and reuploaded it, Youtube will probably take down the copied content. Just explain what time and effort was involved in copying, encoding, making improvements, editing, whatever for say historical purposes... and that the other uploader just took it wholesale.

When I had this problem a few years ago, not my original material but heavily edited and restored, I first sent a PM to the other uploader, suggesting that he put mine in a playlist on his channel and remove his copy. Only when he refused to comply did I send an infringement notice and Youtube took his down within 24 hours. He'll have got a strike because of that so it's reasonable to give them the opportunity to remove it themselves.