If you're starting a project today and you want to make it easy to interact with the outside world, there are many, many, many services available. If you're feeling overwhelmed with all the options, here's what I'd recommend to get started:
Manage sources with git and host the code, issue tracking, and website on github
Get a blog on Tumblr or Blogger if you want to write extended info about what you're doing, in addition to regular documentation
Set up a mailing list on Google Groups to provide support to your users
Tweet about it on twitter for another easy way to reach out to people who might be interested in short updates about your stuff
After a while you may find one or more of these options lacking. That's a good time to start shopping around and exploring other options. But when you're just getting started and you want to get up and running quickly, give them a shot.