Google algo clue?

found in Google 'cached' results

[bcushion]

While doing my usual 'fruitless' analysis of Google SERPs, I noticed this today when I clicked on the 'cached' area of the results (I added the terms blue and widget):

These search terms have been highlighted: blue
These terms only appear in links pointing to this page: widgets

So G is looking for the word BLUE on page and the word WIDGET in links coming to this page. However, this was alternated with the normal "terms highlighted on page" wherein all search terms are highlighted. (in other words, 1st result was requiring 'term in link', 2nd was both terms on page, 3rd required 'term in link', and so on). Word counts varied greatly, also.
This is the first time I'd seen an 'alternating' or 'rotating' algo(s) on any search engine but I have suspected this use for some time. I would be interested in other's thoughts on this.
(I bring this up also because I am the unproud owner of more than 1 software application that analyses top scoring pages and tells me how to write my pages based on keyword density, placement, etc.... and it seems they may be useless.)

[brina]

Wow, I'm trying really hard to get what you are saying. Can you go over that once more and use "red widgets" as an example? I'm getting confuded because Google is highlighting in blue and yellow.

Thanks, Brina

[Dante_Maure]

bcushion, you're not seeing an alternating algo... what you're observing is due to the fact that Google will display "These terms only appear in links pointing to this page:" when a keyword you've searched for can't be found in the on page text.