Handles large databases. We use MySQL Server with databases that contain 50 million records. We also know of users that use MySQL Server with 60,000 tables and about 5,000,000,000 rows.
It has never happened to me, I guess that the main problem you can encounter when using a lot of tables regards speed: the more tables you join in your requests (especially if each of them has a lot of tuples), the slower you will get the results... Well, that is what sounds logical to me at least!
Hope it helps.
Edit: Sorry I had not seen it was such an old topic