The walls are coming down for all types of media.  Consider the mainstream media.  They are on their way to becoming extinct because people want access to other viewpoints.  People no longer like being filtered by gatekeepers harboring a certain idealogy.

I personally do not like being limited to a small subset of overused images and as alternative search tools get better I think more will defect.

I also think some photographers have been in the stock business for so long they think only commercial image buyers buy images.  My walls are full of prints, many of which were sold as stock.

Though I am not a photographer I have been following these forums for some time as I believe stock photo sales are a good way to take the pulse of the economy.  In addition, I am an occasional image buyer for both commercial and personal use.  The intent of this posting is to express my pet peeves with the current microstock model and to offer an opinion from the non-pro buyer position.  I am not sure if I am typical, but hopefully this may offer some insight into buyer behavior.

Based on my own experience I cannot stand the following aspects of microstock buying and this has greatly limited my purchases to absolute essential buying:

Indirect, cumbersome buying  -  Why can't I just purchase an image and agree to a license like on itunes.  Instead I am greeted by having to figure out credits or buy an expensive subscription.  This one aspect alone reduces my purchases by at least 80% because it is a pain in the $&^^%

Keyword spamming  -  There should be zero tolerance for contributors that include all types of unrelated keywords.  Search for almost anything on typical microstock sites and you gets tons of unrelated stuff.  For example I recently searched for images of children playing basketball for a local youth newsletter.  Probably 70% of the results contained only adults.  After page 3 of results it was bye, bye.

Junk and more junk  -  I agree totally with an earlier post.  After a certain period of time with minimal or no sales images should be removed from the search and only included in the photographer profile.  The way it is currently, you find the spectacular (though often completely staged looking and seen everywhere on the web) images in the beginning pages and then you get to go through tons of pages of results to find something high-quality but "real".

Too expensive for non-commercial  -  Sometimes an image is beautiful or artistic and you just want a digital copy.  For anybody that does not have a subscription the price is too costly in a depressed economy.  Now I know some may be inclined to give me the lecture on production costs, etc... but the reality is customers don't care about this and for such an impulsive purchase they will simply walk away and look elsewhere.

Sorry for the sarcasm and being so blunt.  My intention is not to offend anyone.  It is to awaken some that are receptive to the message.

On one final tip, more and more I, and probably many others are beginning to do their image searches on google.  This way I can search all private sources and agencies at once.  I believe global searches will dominate in the next few years.