Participating in established open source projects (regardless of whether they are on github) is a bit higher visibility than just publishing hobby projects.

Doesn't it take additional proactive work, unless you write some awesome, popular software?

Works like this

Probability of Getting a Job = min((awesomeness of github) * (social skills) * (visibility at local tech events) * (salary expecting to pay / salary asked for),(1))

Where all variables range from 0.25 to 1.25.

Asking for a low salary doesn't really your chances, if you are obviously worth more. People will smell something fishy, justified or not.