The easiest way to talk about different types of companies, especially in cases such as this in describing local vs national companies, is to pin it into an example sector. For the purposes of this I’m going to go with film. A large, national film studio would be likely to get their latest film to have a major distribution deal - theatres all across the respective country, with corresponding areas of interest getting more viewings (for example, a film set in a certain location would have more potential to be seen in that location). A local, and thus much smaller, film would have much more restricted screenings, if any at all, and likely only at small film festivals. The serious cons of national film companies is that whilst they cater for a much larger audience, films can lose their personal creative touch, swamped under a huge budget that over processes everything, but as a pro they often succeed much more than they don’t, whereas whilst smaller film companies can produce creations with a much more personal feel and integrity, they may not even make the film break even thanks to the lack of distribution and also a much smaller range of interest from the public.

Commercial companies are, obviously, profit based, whereas public companies are entirely non-profit and funded by things such as donations and the government. The most simple example possible of these would be commercial television companies versus public television companies - BBC’s television is a public company, funded by TV license fees that are given to every household in the UK, however ITV is commercial company funded by the advertisements that it displays between shows and in the breaks during said shows. There are a few pros and cons to each - people for instance may not necessarily like the fact that they’re forced to pay money to fund a television company, or may not appreciate the content, but also the fact it’s publicly funded allows for a diversity in programmes and chances will be taken. It is not to say that chances won’t be taken on commercial channels, but the programmes will be more geared to simply reeling in a bigger audience so that they can generate more money from the commercials - which they will then use to go on and create yet more programmes that are geared towards a big audience.

The USA market share of the film industry is today split between six big companies: Time Warner, Viacom, News Corporation, The Walt Disney Company, Sony Corporation of America and Comcast/General Electric. These are the conglomerate companies - the subsidiaries of these are Warner Bros. Entertainment, Paramount Motion Pictures Group, Fox Entertainment Group, Walt Disney Motion PIctures Group, Sony PIctures Entertainment and NBCUniversal.

These companies all own several well-known film studios - the best example would probably be Warner Bros., who have their own studio as well as owning New Line Cinema, HBO Films, Picturehouse, and Castle Rock Entertainment, as well as Turner Entertainment. 

This alone shows how huge the film industry is today; Time Warner is the world’s second-largest entertainment/media conglomerate company, staying behind Disney in terms of revenue. Whilst film is a major part of what Time Warner does, they cover a great many things - they own an animation studio, DC Comics, and their television ventures include HBO, Adult Swim, CNN. They also own many website services, magazines and even some radio services.

The film industry has changed and shaped itself into an entirely different and more complex beast in comparison to one hundred years ago in the early 1900s, when film theatres were just starting to exist and everything was silent. Now, those six huge companies take up a massive 85% of the market share (as of 2010), and films are complicated and branch into many other industries, often coming with video games and toys and many items of tie-in material.

Many of these industries cross over with one another, closely working together and relating, creating franchises and goods branching off one thing or working together to create something entirely new.

As already mentioned, animation finds work in the film industry (for example, such hits as the Toy Story and Shrek franchises), in television (anime series, and such series as Creature Comforts), and games, as well as producing popular advertisements (one such recent animated advertisement is the recent singing adverts for confused.com).

In recent years, the games industry has begun to cross over into the film industry. Whilst games, once they became more developed, did take up voice actors, they seemed to always literally just be voice actors - but now, often full actors are cast, to do both the voice and serve as the likeness of the character and film for motion capture. A good example of this cross over is Heavy Rain, who cast actors, such as Leon Ockenden in the role of the Norman Jayden, and had a heavy focus on a very cinematic feel and look as opposed to simply looking like, well, a game.

As well as this film approach to creating games, many films are born as adaptations of video games and vice versa - the Resident Evil games lead to the birth of a film series, and more recently, the release of a new Tron film inspired the release of a new Tron game. They take inspiration from one another also: there was a film adaptation of the first Silent Hill game, and after the film was released, the next game drew on many of the visual themes portrayed in the movie.

The film industry also seems to increasingly cross over into publishing. Many films are adapted from books, and an increasing number of films are adapted into books or have tie-in novels, such as the Pirates Of The Caribbean series which has both prequel novels and books of the movies. Comic books are also more frequently being given film adaptations, and film versions continued via comics.

Television and film have often overlapped, with made for TV films and TV series that have become sequels to films, and vice versa as television series are adapted into movies (for example, The A Team was adapted into a 2010 movie). In a similar vein to that of films being given comic books to adapt and be adapted from, television series are sometimes continued through books and comics once they have reached their on-screen conclusion (as is currently the case with Buffy The Vampire Slayer).

The convergence of industries is more often advantageous than not, as franchises are built upon and built upon creating a greater revenue for all involved. Synergy has long been well-practised to create more profit for each industry in the creative media sector, and as well as being generally good business, the meeting of industries often simply provides greater things for fans of the result - be it a cinematic game or a comic adaptation of a movie.

There are many different industries to the creative media sector. Many of them overlap, some of them where they may not have overlapped quite as much a few years ago - such as that of the games and film industries. A number of these industries are:

• Animation
  Animated content can be found just about anywhere, from being the entire format of big budget films to being a simple little three-frame commercial on a webpage’s sidebar. Despite being a relatively small area overall, it is possibly the most overlapping of the industries within the creative media sector, stretching across games, film, and television, as well as being highly associated with the advertising industry.
• Games
  The games industry has greatly expanded over the years with massive leaps forward in technology and animation capabilities. Games and entertainment sales now go beyond those of video rental and cinema box office sales, and games have an equal chance of becoming a world wide hit with an expansive franchise as movies have.
• Film
  The film industry is a multi-billion area, producing both big-budgeted blockbusters and small budget indie films. In a sense it’s fairly fluid, in that often production companies are set up solely to create a film and then shut down when production is completed. It is still one of the biggest forms of entertainment today, although film theft and downloading is harming it severely.
• Publishing
  A massive part of the creative media sector, publishing covers books, journals (both online and not), newspapers and magazines, business media, directories and newsletters and reports. 
• Photo
  The photo imaging industry covers all image producers, retailers, picture libraries, manufacturers and their support system. Images are a hugely important part of day to day life - they liven up what we read and capture our attention. 
• Radio
  This particular industry has been going for a long time. Before the event of television, the radio was the main form of entertainment in the home, and to this day it is still a popular source as such. With more mediums to host audio shows other than radios itself, the existence of it is changing fast.
• Television
  Something that almost everyone sees in their day to day lives, television programs and the industry behind them all are almost everywhere. It’s a giant area, with the biggest production companies hiring thousands of people in a year.