Hmmm.. this is not a small question.
There are various methods of collating results from more than one database depending on the databases in question, are they all the same for example (MS SQLserver or Oracle ir MySQL) and are they on the same server or spread all over, in one domain or several.
I suspect buzzle.com has one database in which each entry has a type atribute (chapter, article or link)
example:
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| Table: Content |
========================================================
|ID |Type |Keywords |URL |
========================================================
|1 |Chapter |buzz buzzle |
http://buzzle.com |
|2 |Article |buzz buzzle |
http://buzzle.com/articles/buzzle.asp |
|3 |Link |buzz buzzle |
http://buzzle.com/links/index.asp?id=1234 |
========================================================
The SQL query to retreive the data:
SELECT * FROM content WHERE keywords LIKE '%buzzle%' ORDER BY type