For example. I want standard like "user uploaded new video email from YouTube", but only if the video is about certain something/keyword match. Like following a channel only for a series they publish. Like an RSS feed. Is that possible?
Technically you wouldn't be able to set the account or notifications up in that exact manner, but there is a fairly simple to do something very similar; it only requires slightly more effort.
The idea of the setup is this: You are going to be able to access some notification options regarding the page you are subscribed to, but some will still be missing; which is where Gmail comes in, because you can change a few things based on the emails you'd like to receive.
First (being as non-specific as possible) you need to go to YouTube, and get to your subscriptions. Go ahead and click this link to get exactly where you need to be (as long as you're already signed in).
It is very simple - find the Subscribed channels you want notifications for, and on the right-hand side of each one, choose the little bell icon and select what you want sent.
If you are unsure if they will go to your email, you may have to change the settings in the actual account too - but if you're getting them now, you will continue to get the ones that you keep.
Next, assuming you're using Gmail, you will just go to this site here:
You will have the Filters menu up at that point. You can do it in so many different ways, but you said you only want the alerts if they are from a certain Channel and only if they contain certain words...therefore you will sit it up like this:
Scroll down and click Create New Filter
You will need to create at least two (2) because of how specific you want it to be. I cannot tell you what exactly to put in them, but if I were you I would make this the first one:
In the section that reads "Has the Words" you should put something like New and in the same box, type the exact name of the channel you'd like to get emails regarding. Make sure it is exact.
Then, press "Create with this Filter" (or very similar wording) and on the second page, you'll want to choose where you get the emails from that channel about new videos - you can make a special folder (which I recommend) or you could simply check the box that says "Star It" or "Mark Important"... once you've selected one of those options, click "Finish".