In your view, what metric(s) can measure bitcoin adoption?
It would help if bitcoin payment processors released monthly reports on volume processed, with at least a crude breakdown on kind of businesses served (gambling, exchanges, material goods, travel&lodging, ...).
That would give an idea if bitcoin use is increasing, but would still have some limitations, e.g.:
* it would measure bitcoins being sold for dollars to purchase, not people buying bitcoins;
* it would not include people paying with bitcoin directly to merchants that really accept bitcoin
It may also be distorted by people paying to themselves:
https://bitcointalk.org/index.php?topic=150803.msg8916727#msg8916727But that is the best data I can think of that might be available one day.