bohm hit the nail on the head. The website won't snag anyone who's looking at it cold. It might help a little in cases where JWs meet someone preaching, and they go do a web search afterwards, since they may just find jw.org and only go there.
The only case where I can see it having any significant impact is in cases where someone has some personal exposure to JWs outside of the ministry. They may get curious and look up the website and if they're sufficiently impressionable and sufficiently disenfranchised with whatever religion they were raised in, they might get caught up in the cult. This is probably the main way they get recruits anyway though - acquaintances of JWs, not the d2d preaching.