A quick check to the "robots.txt analysis" page revealed the cause of this disturbance. It tuns out that Google (Blogger) has created a default robots.txt file on all blogspot blogs, with the following lines included:
User-agent: *Disallow: /search
This change has resulted in all of the label search pages in any blogspot blog being excluded from the Google index, as well as from the index of any other search engines that obey the robots.txt exclusion protocol.
I don't know why the blogger developers have decided to do this, but I certainly don't enjoy the consequences. A large portion of my traffic came from search engines to my blog's label search pages - I will now lose all of that traffic. Also, it makes sense that when people search for "flora nature photography gallery" they will want to go to the flora search page on my nature photography blog.
Regardless of my traffic loss, the robots.txt addition is here to stay. What are your thoughts about this recent change to blogspot.com blogs, and most importantly: Do you think that this exclusion will have good long-term effects on the blogosphere?
David's Nature Photo Gallery