Publishers using Adbrite can backfill inventory with Google adsense but have to record the price to beat so that Adbrite knows when to serve their ads instead of adsense (they favor those which drive more revenue). Note the last part of their statement in parenthesis about gross eCPM. Are they highlighting that you have to put in something other than the eCPM google reports for your campaign? Does Google's eCPM take into account their revenue share? By the way, you can run local advertising with us (Zvents) here