Does Google change their algo to give rank position?

[Cyclob]

I come up with this question because I've been checking my position in google lately in each keyword and my position have changed a lot. Most of them they drop like from top 10 to 80 or some keyword more than 100.

I didn't do anything with those page but I noticed that in the title of search result, it's not quite exactly what I put in the search box. It will give the weight in most common word that I put in. For example, if I put " AAA hotel london" , the most common word which is london will come up in search result instead of what I put in. And that makes me nowhere...

I'm kind of wondering right now. Anyone know something about this....please....

[vitaplease]

yes, with a multi keyword search query, very common included words mean more competition, unless you make it an exact search (search querry between "...")