The Real "Prevention"
Encouraging people to put in filters and warning them of the dangers of the internet is good, but these are just "patches". The real prevention is something else entirely. After all, even with filters, our kids (and ourselves) can still buy an unlimited internet access cell-phone for just $40 per month (in NY anyway). And the rates keep coming down.
We can access the raw web in a gazillion places through more and more devices (GPS systems, even!) and its just going to get worse.
The key to REAL prevention is:
1) Working on Middos. That's what 12-Steps do too. They don't have pep talks lambasting lust or alcohol etc. Instead, the 12-Steps help you develop the right attitudes to living life with Hashem.
2) Working on parenting. In my generation, the kids grew up mostly like weeds. Which parents spent time talking to their kids? But today, it is imperative that parents speak daily to their kids, be part of their lives, ask how their day went, etc.
Resources like R' Brezak's parenting line (Project Kavey... weekly recorded information) and Dina Freidman's 1 year parenting course (by phone) - are essential! (Dina Friedman currently has about 800 mothers per year. My wife is taking it now and it is really beneficial.)