I am planning to make an application to digitalize and organize documents a company, or forum, etc may have.
PS: hope i did'nt do wrong posting this here aswell and i am sorry about my poor english.
The fastest place to start your research is through google. Search on the terms that describe your product and see if someone is already in that space. If no one is in that space its possible that there is no market for it. If there is a lot of people in that product it maybe difficult to get into. If though a few new products have gotten into it it might be an emerging market niche.
I normally go to download.com or some other software site if it is for the desktop to get an idea of the download counts also if a web 2.0 service I'll look through the search terms in google to get an idea of number of searches per month, if it is trending up and about how much it would cost to advertise for the wording (search term competition) that desribes the product. With this you get a rough idea of market size on the internet.
In the end though you will want to find the people that would be the customer and ask questions to them and see if there would be an interest in buying what you are planning on creating. If you can get some commitments or interest with the above quick interenet searches I think you can go into that market and give it a go.
This is a new question, but not a new idea. It has been done before, and it has been done by huge influencing companies. You will, and I mean for sure you will, have a hard time getting started. Thats not to say that you can't have any profit at all.
You want to digitize and organize documents, this is already being done by Google Docs. Its what I use to keep an online copy of all our documents.
Anyways, read 6 Strategies to Take On an Established Competitor
I would try to talk to some prospective customers first. Find out from them what the competition is doing wrong and build a better solution. That doesn't necessarily mean just a better technical solution, but something that lets your customers achieve their goals better. Don't look at what your competitors are doing, try to figure out what they are not doing. Research on the internet can only get you so far; get out there and talk to people. Get some people interested, build the system, let them play with it, improve the system, and start selling it.