Sure. I use CRON-O-Meter (http://cronometer.com/) to track my diet and weight, RunKeeper (http://runkeeper.com/home) and Fitocracy (https://www.fitocracy.com/) to track exercise, Moodscope (http://www.moodscope.com/login) to track my mood, and YourFlowingData (http://your.flowingdata.com/) to track anything else I want to measure. My favorite self-tracking service was an MIT Media Lab project called Mycrocosm (http://mycro.media.mit.edu/), but it's pretty much dead. (I wrote a Python script to extract my old data. I'll clean it up and publish it).

Some of these services are completely siloed, some of them export data as .csv or XML, and some of them actively interact with one another (e.g. Fitocracy imports Runkeeper data, CRONometer can connect to a Withings scale). Each tool works well in its niche, but there's no easy way (yet!) to get all the data in one machine-readable place.