Voiceover forums on Facebook and Linkedin can be a decent place to start when you're considering a voiceover career but they are not a replacement for voiceover training. Some talents tend to get too comfortable participating in dozens of these groups daily. It's like working in a corporate office and spending too much time going from cubicle to cubicle socializing. It's a time suck and can become quite the distraction.
You'll find plenty of good information in VO forums, but some of the advice can be misleading. These days, everyone is a guru on social media no matter their experience. Everyone wants to help! If you're passionate about learning the business, too many visits to the wrong group can spin you out! Stick to groups that are moderated by seasoned professionals.
Suppose you come across some advice that leaves you scratching your head. Google the person who created the post or made a comment. You'll find out in a hurry how credible they are.
VO forums are a fun place to hang and you can meet a lot of friends in the business but forums don't provide one-on-one coaching, nor will they produce professional demos for you. So instead, consider them a part of your research and then move on to getting some quality training.