MathOverflow will be down for maintenance for approximately 3 hours, starting Monday evening (06/24/2013) at approximately 9:00 PM Eastern time (UTC-4).
    Post Made Community Wiki by Anton Geraschenko♦♦
show/hide this revision's text 2 fixed grammar

In addition to google, google scholar, and google books, I sometimes find the following to be useful:

  1. sciencedirect.com --- to search through the journals, and thus by analogy several other publisher's publishers' websites

  2. latexsearch.com --- still in beta, but it tries to search through takes TeX / LaTeX code as input, so might be useful for addressing the .tex filespoint raised in your Observation 2.

Another very recent, though not relevant for you website might be: sciverse.com (for image / illustration search in published articles)
show/hide this revision's text 1

In addition to google, google scholar, and google books, I sometimes find the following to be useful:

  1. sciencedirect.com --- to search through the journals, and thus by analogy several other publisher's websites

  2. latexsearch.com --- still in beta, but it tries to search through the .tex files.

Another very recent, though not relevant for you website might be: sciverse.com (for image / illustration search in published articles)