Using A Separate Domain To Serve All Advertising

[MadMax]

Lookin' for opinions here on something I'm considering. Mods, please move this post if you feel it doesn't belong in this forum.

I've been using PhpAdsNew for a while to serve all my advertising on Fetish Philes from a subdomain. This is working great, but I'd rather be using the same ads everywhere without bogging down the bandwidth usage on Fetish Philes with ads served to other domains.

One way or another I'd like to start serving pretty much all the advertising on all my sites (all the banners, at least) from a single instance of PhpAdsNew so that I can better manage and track all my sponsor advertising.

I'm leaning in the direction of taking one of my unused domains and serving all the ads from there, with phpads being the only thing on that domain (all my domains are hosted on the same box). I'm just looking for some feeback on any downsides of this idea that I haven't thought of (frankly, I haven't thought of any). Is there a downside I'm not thinking of, or is this just a logical step?

TIA for all opinions