How does Google Detect which keywords my website should show up for in the SE?

[FarrisFahad]

When I checked my Google Webmaster Tools I found that my website is showing up for keywords that I didn't optimize for ...

for example I optimize my website for "funny pictures with captions", and the website is showing up for "funny images with captions". I know that this is good, but the keyword is dancing all around,

sometimes I search for "funny pictures with captions" and I show up in the 7th page, and some time I don't show up. and the same goes for the other keyword. of course I am optimizing for more than two keywords but the results is not consistent.

my question is how does Google decide which keywords you website should show up for?

Is it the on-page keywords?, or is it the off-page anchor text keywords?

Thank you in advance ...
FarrisFahad

[Saijo.George]

I am sure if you searched for " ~images -images" before Google decided to drop the ~ operator , pictures would have come up as an alternate keyword and so, they would have seen it as a close match for pictures and served your site for your query.

It was one of my fav tool for finding alternate keywords to optimise for , sadly that is gone now

As for on page vs off page both are important .. it not an "either or" condition you should do both to get good results , especially if the competition is strong.

[brad.s.knutson]

Google tends to "think" for you when running searches.  They often assume like words mean the same thing, so running a search query for "funny images" and "funny pictures" will likely produce very similar (if not the same) results.  You should take this to your advantage, rather than worrying about it too much.

I see this used a lot when I search for "web developer" and get results for "web development" and "web design."  The keywords are bolded as if Google assumed that is what I meant.  I don't think it's a problem, just something to account for in your keyword research.

[Raydon]

Son, if the answer to your question was that simple or known so accurately, those who knew it would be wearing everything in gold!

it is a combination of both of those factors as well as your competition's use of your keywords and others.

Also, it will depend on the rate of new and worthy content creation with relevant and similar keywords included within your website/blog.

it also depends on how popular is your particular keyphrase with searchers themselves, you can use services like google trends, google correlate, and google adwords keyword tool to find out some useful numbers about your targeted kws and their popularity with searchers and competitors (at least with regards to paid ads, but if they know what they are doing they will more than likely use the same kws for SEO as well) alike.

[GrowFuse]

Well those two terms are very similar. Chances are if someone is searching for images they don't care if pictures show up(are they not the same thing?) The reason it shows up on the 7th page is because like you said you don't actively try to rank for it therefore Google does not see it as relevant. I hope this answered some of your questions, if not ask more and I will be glad to answer.