abilitydesigns - 7:48 am on Sep 10, 2009 (gmt 0)

Difficult to take a call on your claim of sneaky tactic without seeing the actual url.

But Google started using technology called optical character recognition ( OCR ) to extract text out of the PDF’s from late 2008 onwards.

What it basically does is that it takes the snapshots of PDF’s as input, runs optical character recognition on them and index the text just like regular text.

If it can see the text, it would be seeing the links too?

If you want to know geek details about the open source OCR software that Google sponsers, OCROPUS –
refer to: [code.google.com...]

(If you have Acrobat Pro 9, you can see the option under Documents => OCR Text Recognition => Recognize Text using OCR)

-AD