1. Identify the site in question
2. install a plug in such as Leechblock or StayFocused.
3. Allow yourself 20 minutes on that site a day.
4. You get thrown out.

Plus points of this are:

1. Your mind gets focussed on what’s really important about your interaction on that site.
2. You have more time to play Bejewelled
3. You realise there is more to life than online fora.
4. Your stress levels and blood pressure tend to be a bit healthier.

Worth doing. 386ing yourself is not good. People being wrong in bars gets limited by barmen asking if you have no homes to be going to. You need an equivalent for the internet.