The trouble is that some companies treat 'press releases' as chances to get advertising for free. Drobe is a news site, not an advert site. If you want to give us an advert to drum up your sales, then go buy a google ad - that's what they're there for.
For things that matter and of are greater interest to the majority, it'll get on the front page. For things that don't matter (X has 10% off, etc), then it's simply a case of how much other more relevant news there is floating about at that particular time (as well as editors workloads). If it's a quiet day (as someone suggested above) then the chances of mildly interesting/boring articles appearing (flame of the week style, and others very close to being advert-like articles) will probably be greater than normal.
It may be an idea to have some sort of sub column purely for adverts / upgrade announcements, but that is Chris W's decision.