The advanced search tools should be more advanced, like being able to exclude results.

Not only should there be a way to exclude results based upon particular attributes, there should be a way to control whether multiple parts of a query are intersected (treated with logical "and") or united (treated with logical "or"), or for that matter, combinations of these operations as an expression in a formal language.

For example, I would like to be able to search for titles that are rated G but also not animated. Without a plot keyword such as, say, "live-action" in regular use (or applied automatically on title entries that do not specify the nature of the work), there is no way to filter out cartoons, stop-action cinematography or computer-generated pictures.

Some get-us-up-to-speed information...

The query string of the URL search results listings is organized into a collection of parameters, some of which accept as values a comma-delimited sequence of movie/person properties. For some parameters (such as ones that do not have numeric ranges for values or are not special), the commas ultimately function as either the logical operator "and" or the logical operator "or". An example of such a URL is http://www.imdb.com/search/title?genres=biography,history,war&title_type=feature,tv_movie,short: "Most Popular Biography-History-War Feature Films/TV Movies/Short Films". Each result is a title that belongs at least to all three of the genres "biography", "history" and "war" (an intersection ["and"] operation), while also being any of the types "feature film", "TV movie" and "short film" (a union ["or"] operation). In title of the results page, noticeably the genres are separated by hyphens whereas the types are separated by forward slashes.

Some of the possible parameters in advanced title searches are as follows:

• certificates, which can have any combination of the values "us:g", "us:pg", "us:pg_13", "us:r" and "us:nc_17" (and likely more) which are ored together;
  
• colors, which can have any combination of values "color", "black_and_white", "colorized" and "aces" which are ored together;
• companies, which can have any combination of the values "fox", "columbia", "dreamworks", "mgm", "paramount", "universal", "disney" and "warner" which are anded together;
• genres, which can have any combination of the values "action", "adventure", "animation", "biography", "comedy", "crime", "documentary", "drama", "family", "fantasy", "film_noir", "game_show", "history", "horror", "music", "musical", "mystery", "news", "reality_tv", "romance", "sci_fi", "sport", "talk_show", "thriller", "war" and "western" which (as stated before) are anded together;
• groups, which can have any combination of the values "top_100", "top_250", "top_1000,", "now-playing-us", "oscar_winners", "oscar_best_picture_winners", "oscar_best_director_winners", "oscar_nominees", "emmy_winners", "emmy_nominees", "golden_globe_winners", "golden_globe_nominees", "razzie_winners", "razzie_nominees", "national_film_registry", "bottom_100", "bottom_250" and "bottom_1000" which are anded together (which in some cases nullify the outcome [but that is no big deal]);
• keywords, which can have any combination of alphanumeric strings or hyphen-separated alphanumeric strings which are anded together;
• online_availability, which can have any combination of the values "US/today/IMDb/free", "US/today/Amazon/paid", "US/today/Amazon/subs", "US/today/Amazon/subs", "US/today/WithoutABox/free" and "US/today/Internet Archive/free" which are ored together;
• production_status, which can have any combination of the values "released", "post_production", "filming", "pre_production", "completed", "script", "optioned_property", "announced", "treatment_outline", "pitch", "turnaround", "abandoned", "delayed", "indefinitely_delayed", "active" and "unknown" which are ored together;
• role, which can any combination of person keys (for example, "nm1000000") which are anded together (["collaborations and overlaps" in other words] one of IMDb's best features, by the way);
  
• title_type, which can have any combination of the values "feature", "tv_movie", "tv_series", "tv_episode", "tv_special", "mini_series", "documentary", "game", "short", "video" and "tvshort" which (as stated before) are ored together.
  

The above is a partial specification of the system in place. I do not yet have a detailed proposal for what would be even more advanced and improved, because there are lots of contextual nuances (of how to apply set theory) to sort out.

By the way, the techniques presented in the IMDb GS topic "Excluding genres in advanced title search" are outdated or inaccurate. To elaborate on that point, we will note that http://www.imdb.com/search/title?!genres=comedy,music&genres=documentary produces the same results as http://www.imdb.com/search/title?genres=documentary does.