If you're familiar with any kind of forums, Reddit has a very intuitive and easy to use user interface. It has a huge plethora of "subreddits" based on subject or interest, and many of them are professionally oriented. The work-related subreddits in particular have a culture of collaboration and friendliness, and they're great for online networking, learning from others, asking and answering questions, sharing tips and job leads, and crowd-sourcing solutions to problems. Review collected by and hosted on G2.com.
The search function could be better, as the results aren't always organized in a way that makes sense. It can just take a little bit of playing around to get what you need from the search function. Review collected by and hosted on G2.com.
