From which sources come earnings informations of various stock agencies, and whether we can trust the accuracy of the same?

Do you mean the ratings on the side to the right?  They are a 3 month average of people voting on how much they are earning each month on the various sites.  You can vote once a month on this page
http://www.microstockgroup.com/index.php?page=microstockmonthlysurvey

Or go up to Polls > Submit Vote

In answer to the last part of your question, it is impossible to know if the they are accutate or not.  We just have to rely on the honesty of the members  that participate.

In answer to the last part of your question, it is impossible to know if the they are accutate or not.  We just have to rely on the honesty of the members  that participate.

^^ Right.  And even if it were accurate as an average, results do vary between artists depending on what you shoot, how good you are aligned to buyer needs, volume, differentiation, etc.  It's a good indicator is all.

Quote from: fotografer on March 13, 2013, 13:59

In answer to the last part of your question, it is impossible to know if the they are accutate or not.  We just have to rely on the honesty of the members  that participate.

^^ Right.  And even if it were accurate as an average, results do vary between artists depending on what you shoot, how good you are aligned to buyer needs, volume, differentiation, etc.  It's a good indicator is all.

exactly.  and yes, the results are primarily for photographer.  Illustrators and videographers would have a very different set of results.