My reasoning around Github is that you guys are engineers and are obviously going to gravitate easier to your brethren and make it easier to develop/refine your featureset. Making it for everyone is hard as we all have competing interests. The thing about having immediate content available from my past makes it easier for me to contribute without having to come up with something to make the app immediately useful for me. The first engagement is the most important and will help the user decide if the app is worth it or not. That's why I always use gravatar yet allow the users to add/edit their photo in my apps. It's a personalized welcome, like they do at nice hotels.
Don't worry about the UI too much. A good one requires a professional to focus on that alone for awhile to get it right. A good one costs money. That can all come in time.
Google analytics are fine, there are some other packages out there that you can slip on, but when I do usability tests, I measure exactly how many clicks each button/action receives and valuate their purpose to the app based on those metrics, so yes, some internal metrics will be very valuable to you in order to dole out resources to the app, and if you're so inclined, give some light metrics to the user to show them how many times their particular project was visited. It's a cheap trick (like karma) but people are people and they enjoy validation.
Also, if you think of it, listing the number of active projects in your app on the homepage is another easy come-on and helps conversion, just like McDonald's has been doing for decades now.
