I have been using a journaling app called Day One for a bit over a year (Mac and iOS.) Day One allows you to keep a journal on your Mac or iOS device. The entries are saved in iCloud so basically any entries you make on one device, appear on the others.
I have mainly been using it to jot down notes and reflections about my day at school. For example I might add a note during or after a phone conversation, or after a classroom visit, and I try to jot down each evening reflections on events and activities that have taken place at school. Over the course of the time I have been using it, it has undergone a number of upgrades that have really made it one of my favorite and most useful apps. Day One can grab meta data associated with the time and location of your entries. For example it can grab the location information associated with where you are at the time of the post, and also grab weather information for the time and location. One feature that is nice is that if you import an image into an entry, you are given the option of using the date and location data associated with that image as the date and location stamp on your entry. It also allows for tagging of entries.
Recently I have been experimenting with a tool called Slogger that integrates with my Day One journal. Slogger is an app devleoped by Brett Terpstrat (@ttscoff) that can pull data from various social media posts and makes entries in your Day One journal. For example it can be set up to pull images one has posted to sites such as Instagram or Flickr as entries into your Day One journal. In addition articles and posts saved on read later services such as Pocket and Instapaper can also be noted. Foursquare checkins, RSS feeds, and Twitter posts and favorites are also options.
Check the Slogger link for a list of services supported. Also note that the app runs in Terminal, so it involves getting under the hood a bit with the command line. Also note that for it to work properly, it needs to run once a day, every day. Brent explains how to do this in his very well detailed installation notes.
I am finding that I like being able to mix my social media posts along side of my journal posts. I also like having an archive of arranged by date.
Finally I wanted to point out a great series of posts by Tulio Jarocki, @tuliojarockicom about using Day One as a journaling tool. Lots of great suggestions for getting started and organized.
