Very easy to do with IFTTT and Pushover.

1. You need to add a Pushover channel to IFTTT once you’ve signed up with Pushover.
2. Create a recipe with the “if” = RSS feed channel “new feed item”. The “then that” part is the Pushover “send a notification” action.

So, whenever a blog or site is updated, it will send you a notification on your phone.

Note: IFTTT is great for doing all kinds of notification like this. It can be used for all kinds of automation between tons of services. But I primarily use it to have it send me a notification if my wife adds a calendar event to our shared family calendar. I have also used it in the past to send me a notification when a new fluther question is posted.

Oh I absolutely agree, IFTTT is awesome service, I use it for all the social accounts I have like Tumblr, Flickr and so on. You can create all sorts of triggers and actions thanks to it, try it, it should work. Also general info about IFTTT just in case, I got some problems with posting info from my RSS to my FB account, so for this particular action I used Dlvr.it But for all the rest, IFTTT is the best