What is needed in Klal Yisrael today is not merely prevention of addiction, but a whole area of avodas Hashem through which a person, by defeating his yetzer hara daily, can be zocheh to great z'chuyos and to be poel yeshuos.
In serving Hashem, there really is no such thing as "maintenance". As numerous sefarim say, a person is either getting closer to Hashem or moving further away.
Those who use the internet daily without sinning are like the Shomrei Sh'viis, who shecht their yetzer hara daily through watching their field and each day resisting the urge to work on it. In fact, the gemara (Kiddushin 40a) uses the same pasuk to describe those who pass a test of sexual immorality (which of course includes seeing forbidden images) as it does those who keep sh'viis! Each is described as "those who are mighty and strong who do Hashem's will, to listen to His voice!
They are like Rav Chanina and Rav Oshaya (in Pesachim 113b) who fixed the shoes of prostitutes for a living and never looked at them, that Hashem announced their greatness each day throughout the heavens and were called the holy rabbis of Eretz Yisrael. They are the mighty heroes of klal Yisroel!
Anyone who performs the feat of using the internet without transgressing should thank and praise Hashem for each day he merits to do so!
In my humble opinion, Hashem is bringing all of this about in order to lift Klal Yisroel to a greater level of pnimius in avodas Hashem . Anyone who is not among those who strive for closeness to Hashem, has some inkling of how far away he is, and attempts tshuva daily may easily fall, rachmana litzlan . All the more so those who have transgressed are being forced to reach and explore deep inside to discover a whole new appreciation of what it means to be a Yid in all areas.
Even though I am a baal teshuva, product of Litvishe yeshivos, I have arrived at daily Breslov-style hisbodedus as the best way of fighting this battle--davening for siyata dishmaya and confessing to Hashem even concerning "minor" infractions and davening that it shouldn't affect my neshama ...
(By "minor" I am referring to that which the Shulchan Aruch says, "Anyone who gazes at the little finger of a woman with intention to have pleasure is as if he stared at her most private parts." [Even Haezer 21] It is nearly impossible to be in a workplace with women and to be completely free of this sin.)
Filters alone are not enough. First of all, the filter will not help me at the store or workplace... And second, I found my Yetzer Hara was saying, "try to circumvent it - it won't stop you." I realized that it is crucial for me to want to guard my eyes. I have to be the filter; I can't fall into the trap of giving the responsibility for my kedushas eynayim to a filter. Whatever filters we have need to be coupled with yiras shomayim.