It is funny that you feel this way. I started a restaurant CMS (http://sourceforge.net/projects/menube/) years ago, back then GrubHub was a crappy jsp website and a competitor. I even offered to share my software with them:)

I am impressed with their success as a business, technology has never been their strong suit, apparently despite having grown to hundreds of employees.

Those two guys are real entrepreneurs:)

I used to get an error page any time I would enter my address on Grubhub with no other options, but Seamless/Delivery.com/etc worked great.

Geocoding is relatively tricky, was there something weird about your address?

US addresses in major cities (where these companies operate) is largely solved, though. You can just defer to Google Maps (who have the best geocoder I've ever used- still) or set up a GeoCommons geocoder locally, which isn't anywhere near as good, but does work with well formatted addresses.

Not at all. <Street Address> <Apt Number> New York NY 10027. It would present me with three "corrected" options that were all the same, and then when I chose one it would send me to an error page.

Speaking from experience... apartment numbers are one of the most difficult things to process correctly when geocoding, particularly if your service is backed by Google. The experience you describe sounds exactly like someone didn't correctly handle the edge cases surrounding subunit numbers.

I spent quite some time banging my head against these issues for a former employer. Lots of trial-and-error was employed to build up a basket of test cases around apartments. Certain addresses remained intractable.