You can create Google Alerts at http://www.google.com/alerts/
with certain keywords to track certain keywords (like for
1) advertising campaigns (also use Google Trends)
2) tracking companies
3) domains (like Tyres in Poland)
Use Gmail older rules or MS outlook rules to direct the emails to certain folders to avoid flooding your inbox.
DECISION STATS 
Have been doing this for a while – I get alerts on things I both blog about and am interested in. Works great. I like your suggestion on using filters.
Peace,
Charlie~