I've searched around quiet a bit for an answer to my question but haven't been successful so now I hope that the members of this great forum can enlighten me with a satisfactory answer.

Ok so my question may sound like a newbie one and for that forgive me but in all my other web applications using db's one database containing all tables did the job just fine as they were not too full with content. But my newest database driven site is a very large-scale social networking and resource site and for that reason I have the following question:

Which is better structure, 1 database with all tables needed or many databases with 1-2 tables in each??

I hope you can help me with this and apologies for the long intro.

Thanks in advance!