The promise is on their website: enter Your Twitter name and they estimate Your earnings with Be a Magpie.
My Twitter name promised about $500 a month.
I signed up the service.
After 1 day, there had been the first advertising campaign to post on Twitter. Yesterday, I posted my first Be a Magpie advertising.
$0,- earnings so far.
Now I have the message "7 days to next tweet, all Your campaigns had been just used"
All my campaigns? There is only 1 campaign not well targeted to my Twitter account.
When it remains with 1 campaign and a Tweet only once a week,
the monthly earnings could be $0 instead of the $500 prognosis.