Another bug for ya -- searching for a specific file, I find that the search box malfunctions in a very specific way if you try to type in a query containing an underscore. The underscore doesn't appear and a noise is made. It almost looks as if it's being deliberately rejected; but that, of course, makes no sense as it's a common component of file names and therefore often needed to narrow down a query when a specific file is sought.

(The query language is also woefully simple -- it just seems to be an AND of the terms. Quoting a phrase will not result in an exact match being required, even -- the words in the phrase can still apparently match the query by occurring separately and in any order, and not just sequentially in the specified order. There's no OR facility, though you can kludge that by doing multiple searches. There's no apparent way to wild match "a single character or nothing" either -- it'd be nice if the query le?ann matched both leann and leeann and le*ann matched those and leighann as well, just as an example. Of course, with those and quoting, we'd need a way to match actual question marks, quote marks, and asterisks; say a backslash preceding any of those, or for a literal backslash, preceding a backslash. This would be nearly back-compatible since normal queries are just alphanumeric with some spaces anyway, but advanced users would be rewarded by the additional options when they had a tricky query.

A NOT function might be nice too, if most of the hits for something are turning out to be irrelevant. You can try to craft the query to reject the irrelevant results.

Anything that enables more narrowly targeted queries helps the network.

Google's search options should be your model here -- you can match on date or site (site is, admittedly, irrelevant here), as well as name and size, and the name can include exact phrases, "near", "not", and "or" words, and so forth. And this is without really getting into the "advanced search" options...