If you were looking to create a web based service or product in a specific area, how to you go about determining the competition? Would you say a keyword search in Google that returns less than 1M results, but is also keyword that is trending low competition and worth pursuing? What are the numbers you look out for during your research? Do you base your competition on the amount of returns in Google for keywords, if results were tens of millions, would you drop the idea?
Take a look at google keyword tool and see how much people are searching for this product. Next go to google trends, and see if it's still goes up or it's not so often used search term as before. Than, google search, check pages manually and see how many real competitors you have. After you got all results do the math yourself. If you don't know, just do it. If you fail you fail, if not, your problems are over. Remember if there are people who searches your service, you will always be able to get a piece of pie.
You are going to get MANY different answers on this. Over the years I've heard anything from less than 10,000 along with other numbers. I've also heard that you shouldn't touch a market unless the cost is $1 or higher on Google adwords. Also, how much money do you have to invest in the website AND can you really do better than others already in the market? To me that is the most important question. What is "different" about your idea/site and how does that make it stand out from the crowd. I'd look at that before I considered anything else. If you can't offer people something new and valuable, then why are you trying to setup the site or enter the market?
Long statement short, the ones that appears on the results page whether they are on the same industry or not, can be considered as your competition. Also this is regardless of monthly searches.
It sounds like you are trying to find a market with limited competition? If so, just keep in mind that limited competition is a double-edged sword. Yes, there are fewer vendors to compete with, but that also means that the market demand will also be lower than when there is a healthy, competitive marketplace generating demand so your products/services sales will also have less potential, at first. Also note that if you do build up a market on your own, competitors will soon follow, anyway.
Do you have something already that you want to offer, but are too nervous about saturation? Or are you trying to find something with low competition to try and break into. Either way, while these things matter to an extent, you are always going to have competition, and if you don't you're clearly not addressing a clear enough need. Find ways to establish and differentiate yourself, while focusing on providing a solution to your target markets problems. Ask yourself questions about your product or service from your customers point of view -- why do they care??