How many ads the system can support - can it support for example 1 million listings?
The database, which is used - MySQL is very capable of handling
data tables with millions records in it.
We also tried to use simple and optimized queries in order to make the site run fast even with a high
number of listings. An exact number of listings is however
hard to tell, because that usually depends a lot on the
server on which the site is hosted, if it's on a shared hosting package or dedicated server, how powerful it is in terms of CPU, RAM and other factors.