Even if you're in a completely legal state, like I am, the more people who know about your grow, the more likely it is someone will know someone who is looking for a target to steal/invade. Loose lips are still dangerous, even for those of us no longer under Prohibition laws.
Yea, this is the single biggest rule. Don't give information that's not needed. So many idiots get in trouble for "bragging" which is easy to do when your creating really fine ganja, but try and keep it too yourself. DON'T TRUST ANYONE.
And this is why I use THCFarmer. I don't talk shop with anyone else. It can be difficult, with the sharing and all - but my experience is that sharing goes badly, eventually. People have died in my area, because of fucking google satellite mapping drawing bad folks from Philadephia, 3 thousand miles away.