The julia-users mailing list is for discussion around the usage of julia. New users of julia can ask their questions here. As a courtesy to others, do check the archives and documentation to see if a particular question is already answered.
The julia-dev mailing list is for discussion related to the development of julia itself.
The julia-stats mailing list is a special purpose mailing list for discussions related to statistical programming with julia. Topics of interest include DataFrame support, GLM modeling, and automatic generation of MCMC code for Bayesian models.
The julia-opt mailing list is for discussions related to numerical optimization in julia. This includes Mathematical Programming (linear, mixed-integer, conic, semi-definite, etc.), constrained and unconstrained gradient-based and gradient-free optimization, and related topics.
Various Julia projects are hosted under the following umbrella organizations on GitHub:
A blog aggregator for Julia blogs
Tweet using the #JuliaLang hashtag on Twitter.
Use the julia-lang tag on StackOverflow, if you post a Julia related question on StackOverflow.
Many Julia users and developers hang out in the #julia IRC channel on Freenode.
Julia has several local user groups:
Don’t have one in your area? Why not start one!
The Julia Language SubReddit is a collection of various blog posts and articles related to Julia.