Cakir's pseudocode script looks like it would work but I'm guessing you would also need to find a way to remove newbies from your ignore list once they turn into junior members right? That would be difficult since you would need to parse through their profiles with an if-then statement. A better alternative might be to cycle through the latest user ID's so that something like only the latest 1,000 or so user ID's are added to the ignore list and those that are older are removed. Or perhaps have the list update every 1-2 activity periods so that accounts older than 1-2 activity periods are removed.
While several new users are shill accounts, there are legit new users too trying to learn more about bitcoin. Welcoming and helping them can make a big difference.
Yup. In fact, it can be pretty fun to read some of the oldest posts made by some of the veteran members here and see how much they have learned and changed since they first joined. I, for example, was trying to mine bitcoins and catcoins on a netbook. Others started off as newbies asking for loans without collateral but are now highly trusted and respected members of the community.
? I think it is needed a sort of bot for this work, an hard and boring work.
this is amazing ! 
