Seems to be an odd occurence happening in Google today. A member on the SEW forums, reported results for filetype:pdf searches are limited to a very few listings. So much so, that only about 1-30 documents only show up up for result sets of over 5 million. The particular query used was: car filetype:pdf, which showed Results 1 - 17 (total) of about 5,740,000 for car filetype:pdf. (1.78 seconds). I went ahead and test this from my location in the US, and were only able to view 11 of the results. I then tested this with some other keywords, such as: education filetype:pdf - resulting in 4 results out of 4,740,000. Just tried the search again, and guess what Google found 5 results this time, and 5,000,000 results! Out of 100,000 servers est. and a nice fault tolerant filesystem, they can only provide 5 results??Something tells me its not quite a screw up.
So what is going on here? Not exactly sure, but one guess would be that Google might be testing filtering of PDF documents for the sake of catching spam in the results. There has been rising indications that more and more people are using PDF's to spam the search engines. Basically they are trying to pervert another means of electronic media on the web. If it is true, its a good step for Google, in order to stifle this before it even starts. Anyone got any other ideas?
Additional discussion over at Digitalpoint - Google PDF Anomalies