Yes, I would say that a public funded libraries subsidizes Bob. It just that I see that as a good, and useful subsidy, as information is a non-rivalrous good.

I'm not arguing from a position of moral outrage that Wal-Mart is being unfairly advantaged by the governments funding of the interstate highway system. They do indeed just seem to be taking advantage of the current landscape. The point is that this subsidy disturbs the market for shipping, pushing it away from a global optimum. It is useful to see how the changed incentives play out and cause overconsumption, and using Wal-Mart as a prototypical example is a reasonable thing to do.

Usually when economists use the term "subsidize" they only mean a government action that benefits someone - since that's all that matters for economic analysis.

edit: note the point of Chronos' original post: that the IHS crowds out other methods of shipping goods. This is true even if the IHS only subsidizes shipping by truck in your "trivial" sense.

FWIW, I agree with wnoise, public funding of a library is a subsidy for the users of the library. If publicly funded libraries didn't exist, privately funded ones would, and those privately funded libraries would charge people money just as surely as a privately funded museum charges admissions. (And they'd probably have a "Second Tuesday of the month is free" special, much like a museum.)

Note: when I say something is a "subsidy" I am attempting to state a fact, not attempting to make a moral judgment. In the specific case of a public library, I think they're overdone and a bit of an applause light but ultimately a good use of community tax dollars. But if something costs tax dollars, and it does not benefit the people taxed in proportion to the amount of tax taken from them, then this is the thing that I am referring to when I use the label "subsidy". (The matter is, of course, complicated because "benefit" is much more nebulous than "direct benefit".)