Are the gazillions of images raising awareness of quality, or are they driving standards down?
Interesting question. It's tempting to want to assume that because of the increase in quantity, there would be also be an increase in the number of quality photos that are available to be seen (where here quality means an amalgam of things that "make you want to look at the photos"). If there are more pictures being displayed generally, then there is some chance that there will be more good
pictures being displayed. If 2 out of every photographers produces good work, or if 2 out of every 100 photographs that a photographer makes are good, then the more that they display, the more good photos will be displayed. It may not be any easier finding the good ones though, since there is more wading to do.
The ease of display may work against that "goodness" percentage, however. If it's too easy to display, then it's easier to put up lesser work, especially since the photographers themselves choose what to display. They may not always be objective.
But the presence of countless great works of literature in libraries, bookstores, bookcases in our homes, hasn't necessarily done much to increase literacy or love of literature, or so it seems to me. I'd prefer to be wrong. That is, just because the good photos are there on countless obscure web sites that hardly anyone visits, does not mean they will have an impact.
But re-reading your last paragraph, I see that you are directing your question more to professional photographers; I am not one. I can see where the increasing web presence of their work would have a great impact, because potential customers can easily and quickly view the works of many pros. I can imagine that this greatly facilitates shopping for a wedding photography, for example. It's a good question whether this will have the effect of increasing quality or driving down standards. In the commercial realm, the internet has in some ways reduced choice among consumers. A small number of large internet vendors seem to have rapidly become dominant in some market sectors, more or less what previously also happened in suburban malls where vendor competition was reduced. Usually, reduced competition is not good.
It's an odd mix, dominant vertical development and widespread grassroots collectives. I cannot guess where it leads. But I tend to question whether this situation is long-lived. There are millions of film SLR's collecting dust in dresser drawers all over the world. Most people who bought them used them for a while then gradually lost interest. We're seeing an explosion in digital imaging, but we shouldn't assume that it will go on forever. Once people get over the gee-whiz factor of putting some pics up on a web site, will they eventually get bored? How many will take the image-making seriously enough to keep doing it, or will the digicams end up in the dresser drawers too?