Any new market or invention goes through certain stages.In the beginning, there are a few small players, which are competing mainly against another, perhaps non-digital industry.Take online gambling, for example.When it was first introduced in the late 1990s, we saw an explosion of dozens of small online betting and gaming sites which were mainly competing against brick and mortar casinos, betting shops and national lotteries.But now, we have seen a few major players dominate the online gambling market and even many governments launching online betting products in addition to their current offerings of land based casinos and lottery tickets.The same can be said about the online book sales market, according to a recent report published by ZD Net Asia.Online book seller Amazon is starting to up the competition against Barnes & Noble in recent times.As a show of friction, the company has decided to withdraw comics from DC Comics from its physical book stores, due to the fact that DC Comics has signed an exclusivity deal with Amazon to make their digital versions available on the Kindle platform and not on the Barnes & Noble Nook.Now, the competition is not only old vs.new (i.e.physical book stores versus online book selling sites), but even online sellers are increasingly competing against each other.This can be partly attributed to the fact that many new players are trying to enter the market and that some brick and mortar book sellers are now launching online services to get with the times.Indeed, there is a lot of content available in electronic format, such as Romance Books , comic books, cooking guides, etc.Some of these books are simply digital versions of books that exist in physical format, while others were created exclusively for online distribution.As such, someone who likes to read romance bookscan find an entire collection of them online at a much lower cost than what they would normally pay for a paper based book.While Amazon and Barnes & Noble are two big sites which sell online editions of books, there are smaller websites that do the same as well.Even though they rarely make headlines, these smaller sites are indeed popular among their clientele, as they often serve a specific niche market.In an article from Online Business Report, Sandra Quatrano, vice president of a website that sells erotic booksin digital format, as well as other types of adult materials, has stated that business has been up by 42% in the past year.As we can see, the industry for online books is starting to get more mature and competition between sellers is starting to heat up.HoweverFind Article, this doesnt mean that there will not be any new entrants to the industry or that there will be no changes to existing websites. RTP Live