Steam now has trading-cards which can be crafted into badges and other marketable items. That link states that trading-cards can be crafted into badges, and that
If you gather another complete set of trading cards you can upgrade that game badge.
However, it also says
Most games will drop a number of cards equal to about half of the number of cards in that game's set of cards.
Does this mean the only way to get the second+ level of a badge is through trading? Or does my "drop counter" reset once I've crafted the badge for that game?