Recently I've been working on a couple of sites on-and-off in my spare time which both have a couple of things in common: they both use MongoDB as a data store and both incorporate the concept of tagging. Using MongoDB's map-reduce functionality is ideal for getting the list of tags, but it does come with its own set of potential issues which are well worth bearing in mind.

Recently I was looking into making HTML 5 a little smaller. I found that not only can you make all the usual tweaks to save space such as removing any instances of div overload and keeping class names and IDs small, you can actually remove entire chunks of HTML which isn't technically required.