If I click on "not interested" does that mean the movie will never again show up in my searches? In the way that would be cool, but on the other hand, it may be something I want to see later so I hesitate to click on it.
I've marked about 15,000 movies "not interested." They will still show up in your searches. They will not show up on the movie recommendation page and they won't show on movie genre lists if you tell it to "don't include movies I have rated". You can undo it by going to the movie's page and clicking on "clear rating".
I use it to mark movies I am sure I will never want to watch. The recommendation system considers it as if you rated the movie slightly negative (kinda like 2.5 stars?). The recommendation system considers a 3 star rating to be neutral.
In the beginning I had around 2418 recommendations on about that number of moving ratings. (I even remember then the latter caught up with and exceeded the former.) In time I began marking Not Interested to things I knew I would never have cause to see (Pregnancy Workout, Bollywood Idol, Gay Orgy, Mob Massacre, Oogly-Pooglies for Li'l Tots). Now I'm about 1718 recommendations on 13100 ratings. I find recommendations to be generally good though sometimes crying for an update after weeks (e.g., after marking half of all Arthur PBS movies as 4 stars yet Netflix predicts I will rate the remaining titles all as 1 star).
I had a lot of movies marked "not interested" and I was getting only one or two recommendations at a time. Someone from the Community Blog said that Netflix thinks you won't be interested in other movies that are similar to the ones that are marked "not interested" so I cleared the rating on them all and lo and behold... I get a lot more (if not completely accurate) recommendations now.
With all my "not interested" ratings, I usually have 150-200 recommendations. I know some people have 1000s of recommendations though. Its working good for me, I really don't want a huge number of recommendations. Just 1 or 2 at a time would be useless too though.
That's my current number, but a lot of the rec's are from 1-5 with very few being in the 20's. I have one movie that is based on 30.
I remember reading on the blog, that rating a movie 5 stars = greater amount of rec's; 4 stars = somewhat less; 3 = no rec's; and 1-2 stars = removing from rec's the ones netfilx finds to be similar. Not intersted = less than the 1-2 stars.
When I was first looking at my recommendations, I decided to "Not Interested" a bunch that I didn't want to be shown again, because I'd seen them. I found out after I became interested in matching people's similarities that it messed with that percentage, so I cleared them and tried to remember exactly how I felt about the movie. (doing it that way, a lot of them ended up the neutral 3).
I did decide to go into genre’s that I don’t care for and mark them all "Not Interested" thinking that might give a clearer picture of my preferences to others. I’ll tell you one effect that approach has. It increased the number of films I’d rated, dramatically. Another was it also increased/decreased the percentages on some of my current Friends.
If you just enter low ratings for movies you don't like, without balancing it with high ratings for movies that you do like, then the site kind of decides that you don't like movies and has trouble finding good selections for you. When I started out I didn't rate anything 5-star for the first week or so, and managed to get into this unbalanced state. Eventually a single 5-star rating for Monty Python and the Holy Grail made the Movies You'll Heart page come alive with tons of good recommendations.
Bottom line, 5 star ratings are powerful, but don't be too cautious using them.