The following are some agility blogs around the net. I have tried to pick active blogs that are not just a personal experience blog. Most will have RSS feeds, email options or social media options. If there is an RSS feed there will usually be a RSS icon on the page similar to this: 
You can usually click on it to open your RSS reader. Often your browser may recognize a feed (either via native facilities or an extension) and will display a similar icon. Note, this is a work in progress - I will add blogs as I find them.