How much do you know about the visitors to your web site? Are they directly interested in what you have to offer them? Is what you are speaking about on your site general information that is available anywhere on the internet, or something that they can only get from you? If you are simply rehashing what everybody else is saying, then you are losing out on a lot of traffic, and a lot of income.
Exactly how much you need to know remains something of a mystery. However, it is relatively safe to say that if you offer only generalities on your web page, you may generate a lot of traffic but you will probably not get a lot of return visitors. While people who come to your site initially, may provide some base ad revenue, unless they can interact on your site, they are probably not going to be very receptive to actual sales pitches from you.
For example, if you are involved in the health care niche, and you only put out a couple of hundred articles about how important health care is, without giving your visitors and readers any real or useful information, it is not likely that they will be returning to get any real information from your site. When you offer them something of substance, no matter whether it is a digital product, or something more tangible, they will remember your mediocrity, and not be compelled to purchase your offerings.
On the other hand, if you have fifty well-written articles, discussing the different types of health care, and different concerns, benefits, and hazards of specific health care needs, your visitors will be more likely to return. When you have something specific to offer those readers, they are bound to be more responsive to your offers.
You can have ten thousand people on your list regarding your particular niche, but are you taking all of the possible variations into consideration, in order to offer something that is directly relevant to your list? That is not to say that you have to get into too much detail, but that you do need to offer them something that is directly related to a specific need. If there is no specific need to fill, none of your visitors will feel a need to purchase it.
While you do not want to narrow your niche down so far that you no longer have any real audience at all, you do want to include specifics about as many of those subgroups in your niche as is possible. Concentrate on building them up one at a time and you will actually fare much better than you would by bombarding them with everything all at once.
If you return to our health care niche example, you could very well start off with a general site, stating the relevance of health care, and how important it is for everyone. That main heading can then be broken down into sub-categories, in order to meet and fulfill the needs and requirements of all of the people that visit your site.
The health care needs of a professional athlete are going to be different than the needs of an elderly and infirm person. However, by including sections in your site to cover the needs of both of those groups, you have expanded your audience by providing more specifics separated into different areas. You have also accomplished this without alienating either group. This is something that is very relevant when you want to generate return traffic or confidence in the products you have for sale on your site.
Whatever particular niche yours happens to be, try expanding it as far as possible while continuing to provide enough information for the casual reader to learn what category they belong in. Offering something for both the general audience as well as more specific information for each of the groups within that arena will only expand your audience, your credibility and your income.