If you think posting photos to flickr is a waste of time, and paying the $24 annual fee for a pro membership to flickr is especially a waste of money, well, my pro membership for the next six years has been paid for by selling this one shot. A person from First (for women) Magazine contacted me by e-mail asking to use the above pug puppy photo in an upcoming issue. I replied, "possibly, depending on the price." The person replied promptly with a price list that was acceptable to me, and I made the easiest money in photography I ever had before. They mailed me the print issue this week (scans above).
I posted the pug puppy photo to flickr on February 11, 2010, not so recently. I do not really post photos to flickr with the thought that the ever might sell. I use flickr to post my favorite shots of the moment, or shots I am not that sure about, and use the feedback I get on the shot to improve my photography skills. I always find it interesting to see which shots get the most views/comments as compared to others. The results are not always what I expect.
So, making the effort to properly publish your photo to flickr, and by properly I mean giving your image an appropriate title, tagging the image with appropriate and creative key words, and writing a full description of the image with exif data and how to contact you for more images/information, if you do this, the results can be one day a nice little windfall comes in the mail for photography work you have long already done.