When I decided to become a freelancer for a while last year, I had a relapse of an old chronic illness: I got hooked on LJ again. Then I went to work in the office, but even such serious measures did not defeat the disease: it was worth typing the address of your friend feed in the browser — and that was it, for several hours they flew away unnoticed to nowhere. The only thing that helped — not to open LJ at all, but then friends were offended: «you don't read me!» Yes, and I quickly found another site that satisfied my information hunger. Of course, this happened in those days when thousands of urgent tasks did not fall on me, but it was still a pity: I have big plans for my development :-)
So, I'm sharing with you what really helped me. This is a plugin for Firefox that allows you to sort the sites viewed daily by categories/tags, and you can allocate some time for each category. It is worth the time to run out — and you will not be able to go to the coveted site. You can, of course, edit the settings, but for this you will have to go to the statistics, where you can immediately see that nothing useful has been done during the day — and the desire to prolong the pleasure immediately subsides.
The plugin is called PageAddict, has a website (where everything is configured), and in addition to text statistics, it also draws diagrams. Oh, yes, I almost forgot: he also really helps.