How to find other people's collections of Classical texts that can be accessed via the Google Book Search and similar mass digitization projects?
How to share one's own collection of such texts with others?
One useful collection can be found at Google Books Ancient Greek and Latin Texts: "Google has digitized over five hundred ancient Greek and Latin books. We present them here downloadable as zip files of images and plain text, and as links to Google Books web pages where you can read them online in full or download PDFs. This collection was selected by Prof. Greg Crane and Alison Babeu of Tufts University, and compiled by Will Brockman and Jon Orwant of Google. Enjoy!" (from the webpage; cf. also the announcement on the Google Books Blog, June 25, 2010).
There is also a Limited Distribution version: "The zip files (...), containing images and plain text, are part of Google Books' research collaboration with Prof. Crane, and are restricted to authorized users within the United States. For authentication, you will be asked for the username and password of your Gmail account." This list of titles can still come in handy, though.
One can also search for full view books with "Teubneri" in the publisher field to obtain a number of Teubner editions.
Edwin Donnelly maintains a list of Loebs with links to Google Books and the Internet Archive, as well as a wider list of Latin and Greek texts and grammars. Loebolus aggregates these PDF's in a single location.
Bruce Robertson's Lace project provides OCR'd copies of many public domain Greek and Latin texts available on Google Book Search and Archive.org.
The classicsindex wiki shares "indices to Google Book Search and other full-text books online" for the study of Greek and Roman classics, early Judaism, and Christianity (the classicsindex points also to Donnelly's lists).
Wiki is obviously a great way for compiling and publishing such bibliographies. It may also be interesting to note that I found the classicsindex via BibSonomy, "a blue social bookmark and publication sharing system" (searching for strings "google greek").
Ryan Baumann's Book Aligner offers scripts to make it easier to identify parallel resources on Google Books, Internet Archive, HathiTrust, etc.
See also: Digital Facsimile.