how long before placements start running

hi canadian84,

From my experience it took sometimes even a couple of days. Here's a couple of reasons why your ad could NOT show on the placements network:

- Low Bid
Upon checking, I found that your placement-targeted ad may not be showing
on the placements you've selected because of a low maximum cost-per-click
(CPC) bid. Please know that on each individual page view, your ad competes
for position with ads from other advertisers. For a given position, if
your CPC bid is lower than bids from other advertisers, their ad may be
displayed instead. You might consider increasing your bids to improve your
ad exposure.

- Too few sites
You may be restricting your ad exposure as you've selected only a single
site in each ad group to show your ad on. By targeting additional relevant
sites, you can increase your ad's visibility.

- Publisher preferences
If an AdWords publisher opts out of showing placement-targeted ads on
their site, your ads will no longer show on their site. Similarly,
publishers occasionally opt out of allowing image ads on their sites. If
this happens and your campaign contains an image ad, the ad will no longer
appear on that site.

Hope it helps.

Regards,
Cristian