Is there a standard when it comes to implementing keyboard shortcuts / accelerator keys for web applications. Example: Navigating through a list of items presented in a grid Are their guidelines on how to implement this? Google has one for GMail in the "labs" section.
Also would it make business sense in investing time for implementing keyboard shortcuts / accelerator keys in web apps
From an accessibility point of view, keyboard shorts are dangerous as they may interfere with the pre-programmed shortcuts of software like screen readers used by visually impaired users.
For this reason, I either avoid their use, or ensure that you can turn off this feature.
Good luck!
I have used a number of web sites and web applications that define their own keyboard shortcuts. They are usually poorly documented and offer little value over conventional mouse-based use.
As Galwegian mentions, you should be careful of interfering with accessibility options, especially if you want to comply with ADA Guidelines for the Web.
You should also test your web app with respect to keyboard shortcuts in popular web browsers. Some people use these, and get annoyed when your web app overrides the browser's keys.
I think it would be more worth your time to test tab order for web forms and other page elements. When I fill out web forms, I tend to use tab to advance to the next form field, but I find some web sites in which a tab jumps to some unexpected place on the page instead of to the visually adjacent element.