In the developer world it is still pretty popular. It's a great way to find quick help from collective developers on a topic. Most large open-source projects have their own IRC channel somewhere, usually freenode.
Go to GitHub, find a project that you like you you've used and fork it. Fix a thing or two, add a new feature and do a pull request. I welcome it when someone does this to my GitHub projects; it's a nice feeling as a project owner that people are using your stuff. Once you've found your groove on what you like to contribute to & you get the chops, start releasing your own projects. Then, as trq pointed out, people start to notice you.
I have to agree with this. It's very rare I see someone straight from college (or with X years experience) not have a junior or mid-level position before a senior position. Many senior positions require a lot of field experience. I'm in a relatively niche field myself, but a lot of the "senior" positions require 5-10 years minimum of hands-on experience in the industry. Just my $0.02.