[shostack]

OP updated this to specify that they saw cockroaches and immediately after saw the ads without searching at all.

The coincidence is certainly odd, but not entirely out of the realm of possibility, especially if this isn't the first time they've had cockroaches (ie. they might be in a demographic/audience segment likely to have these issues and be frequently targeted).

I would also add that FBX partners can leverage a massive amount of 3rd party data, such as search retargeting vendors that can serve ads as quickly as seconds after you've searched for something on one of the data sources they partner with (engines, toolbars, etc.).

[simonster]

Alternatively other people in the same building could have had roaches and somehow made FB aware of it (e.g. status updates), and FB could have targeted him based on his address.