Find similar sites using tag in a table?

Table tags

   web          |    tags                                       |     rank

-----------------------------------------------------------------------------------
    google.com   |search,google,searchengine,engine,web          |     1
    facebook.com |facebook,social,networking,friends,community   |     2
    youtube.com  |video,youtube,videos,entertainment,media       |     3
    yahoo.com    |yahoo,search,email,news,searchengine           |     4
    bing.com     |search,searchengine,microsoft,bing,tools       |     25
    twitter.com  |twitter,social,community,blog,socialnetworking |     11
    orkut.com    |orkut,social,google,community,networking       |     109
    myspace.com  |myspace,social,networking,community,friends    |     53   

Is it possible to find similar sites by searching web and order by its rank for example

search for google.com the result must be yahoo.com,bing.com (yahoo.com is on 4th rank so bing come after yahoo)

search for开发者_运维百科 facebook.com the result must be myspace.com,orkut.com(myspace.com is on 53 rank so orkut come after myspace)

OR ELSE

search by tags and get above result??

NB

Above one is not a final table structure as this for development... final structure will be like this

web      |     similar
-----------------------
google.com | yahoo.com,bing.com,baidu.com,ask.com

etc...

Search by similarity is particularly complex. However, you can do it with cURL to execute your requests and simpleXML to parse response, at this point you can save position of an page on result.

Maybe you want also retrieve the google page rank, you can do it with this class Google Page Rank Checker