If there are a few blogs from which you know you want to read every single article, it can get annoying constantly adding them to Instapaper for later reading. Free web app Instascriber will do it for you.
While many blogs post multiple times daily, some blogs only post every once in a while, and I find those posts, while few and far between, are things I always want to read (a good example is our own Gina Trapani's Smarterware). Instead of adding articles to Instapaper every time a new blog post crops up, it'd be nice to just set them to automatically do so. That's where Instascriber comes in.
Instascriber is a very minimal web app, from which you just subscribe to RSS feeds. It will feed every article from those feeds to your Instapaper account, so you can stop worrying about when those blogs and focus your attention on other things. I certainly wouldn't use it on every blog I read, but it doesn't require any registration and takes about two minutes to set up for the more specialised blogs you like. Hit the link to check it out.