I cAn kinda understand why this happens though.. like someone else mentioned , Mayb the grow took a turn for the worse, and they get embarrassed by how the plants look and simply stop updating.. not everyone has d nerve of say a tafbang n don't care watt others may think or say about their grows, lol..
Another reason Mayb that it was a first grow, n at first they are all excited about things, jtr they soo. Find out that its either more work then they originally thought or that it was much harder, or they simply lost interest in growing and moved on to the next thing..
Some people so may start to get sketched out or paranoid about posting pix of several nicest sized plants in full bloom.. its one thing to post pix of some seedlings as most peps wouldn't worry about getting busted over a few small two inch seedlings , but d paranoia can really kick in when you've git a room full of stinking sativas nearing harvest time..
And lastly, and the one we all like to not to think about too often im sure is that they may have gotten busted, either by the popo or Mayb a significant other tells them that the grow has to go, or they take it down for other security reasons..
Just my $.02 though..