My site had ranked fifth or sixth on google when searching for a certain phrase. A few days later, it dropped down to the second page, but stayed there consistantly for a week or two. A few days ago when I checked again, my website doesn't even show up...I searched the same phrase and checked the first 8 pages and got nothing even related to my site. What could have happened? Did google remove my site?
First use the below advanced search operator in Google... site:http://yoursite.com Code (markup): then check.... site:www.yoursite.com Code (markup): If results appear than your still indexed in Google, i'll bet this was a new web page and\or site and just met the tricky "first page one day, than burried a week later".
If you do the above queries and find nothing check and make sure you are not doing anything against googles guidelines. There are hundreds of ways to get removed by Google. Duplicate content, cloaking, hidden text, keyword stuffing, linking to shady sites, etc... To request re-inclusion you can visit: google.com/support/webmasters/bin/answer.py?answer=35843, it requires you have a Google Webmaster Tools account (which I would recommend either way).
simply, to get back into Google use this : http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=35843