How many keywords
There are two approaches when you start building a website: the first builds the site and all subsequent links around a particular phrase; the second adds as much interesting and useful content as possible, in the hope of attracting the less searched phrases in google and the other search engines.
Most sites will focus on both of these, to a lesser or greater degree, but they require fundamentally different approaches and it helps if you know which you are following, and what your target is.
The first approach is to choose a subject matter that you would like to build a site about, and built the site essentially around that phrase. I’m thinking of a genuinely useful site by the way, not 20 articles copied randomly from wikipedia. For many niche subjects 25 pages is plenty, although must can be expanded later on as necessary.
So typically the site might only contain 15-25 pages, and be reasonably quick to put together. A week or two should be enough to research and write 25 articles about your favourite subject and create a genuinely useful site. If at all possible the domain name will also include the phrase.
After that initial preparation work, little maintenance will be needed on the site. The focus is on getting links to the site, as discussed elsewhere in this blog, built around your keyword and similar variants. Not too quickly, and not always with identical link text. Hopefully your site is interesting enough that others want to link to it. Point is, it is the promotion and link building that will occupy your time, not the ongoing site building.
This can work well, but there is a problem ahead. After a few months of slowly moving up the SERPS you are getting lots of visitors, and decent income from affiliates or adsense or whatever, all is well. Then suddenly google change their algorithm and your site (and income) completely disappear from site - this is the big and real danger of focussing on one phrase.
The search engines do change their algorithms all the time - this week to reduce the importance of reciprocal links, next week devaluing links in free directories, the week after the links from non-relevant sites. No one outside gogle knows what they will tweak this week or next, in reality, but there is a high likelihood that at some point your site will vanish.
On the other hand, if you can stay at the top of the charts for a reasonably competitive word / phrase this can be lucrative, more lucrative than the following approach, I think. So be aware of the risks, and the importance of constantly searching out high quality links, but don’t necessarily ignore this approach.
The second approach - don’t worry too much about keywords, but simply continue preparing lots of pages about all aspects of your subject - is probably the more secure long term route. Each page will perhaps only be found a couple of times a day, but if you have 2,000 pages that adds up to quite a lot of visitors.
Unfortunately even with this approach you do need to focus on link building. Since the search engines use the links to your site to (a) find it and (b) decide how important it is, if you don’t have enough links to both your homepage and internal pages, then the pages will never get indexed, and all you writing time is in vain.
You can enter
site:http://www.yoursitename.com/ ***-view
in google for a list of the pages that are supplemental - brace yourself, it’s not always a pleasant experience - you might well find that 50% or more of your site is languishing in the supplemental results! However there is a little more to it - pages that are shown as supplemental with this query can sometimes show as normal, indexed, pages with more normal queries, so it isn’t 100% foolproof, and isn’t necessarily a cause for complete panic.