As a member for eight years...
I joined up to the site in 2006. When I began, the community was pretty good. For the most part, everyone helped one another, talked with one another, and making friends was fairly easy. Granted, I ran into several issues, even then. In Towns (the flash-based community area where you can have your own house and chat in a certain map), there were more than a few times where I would run into a few people attempting to cyber. Some people, as you can expect, were very rude and intolerant... as is the case on any other site in the world, and its commonplace in real life as well.
Over the years, Gaia's fallen apart. It was once my safety but right now, under new management, it's changed. The community is awful and it's hard to find nice people without an event going on, and the market has been inflated so much that it's impossible for any existing users to get anything they want without paying money, so imagine what a new user would need to go through? Each item released, where it would have once been under 15k in my first years, is now in the billions. Let that sink in a moment.
They way they handle users complaining is simply to either ignore them or shut them up temporarily. They have done very little with our complaints since the inflation began, and likely before then as well. With the growing difficulty to do much of anything with the market, and in turn avatars, the majority of the market is filled with people who purposely list an item far above what it is worth so they can make a profit.
On the other hand, the positives.
The roleplaying community, while many of the topics are very similar, can be some of the best fun I've ever come across. It's a good place to spend time and practice your writing, as various levels of skill are spread across this forum. It's a good place to make friends and meet people with similar interests. Thankfully, with the market the way it is, the "Quests/Charities" forum is the place to go. I have my own quest thread there, one I share with my friend and my mother, who also has a Gaia account. We have gotten a large amount of donations, and people are very kind and understanding.
Earning gold is hard, but it does teach a good lesson; nothing is ever easy to obtain, but getting what you want is worth it when you work for it.
Overall, it is a fun site when you know your way around it and make some friends to play with. Unfortunately, there is no way to completely filter out any of the bad talk and violence without going on a mass banning, which... would really take out the majority of the community.
Parents, be warned. There is no site out there not specifically made for children that is completely safe and 'clean' for a child. If you want a place for them to learn and not be exposed to this 'bad' behavior, I would suggest keeping them away from schools, radio, tv... anything, really, and most certainly Gaia. Otherwise, have at it. It's a fairly good experience.
What other families should know
Too much swearing
Too much consumerism