Power users have been tricking out Google's Chrome browser with extensions for years, and now they can do the same with... Google Docs? Today the search giant launched an add-on store for its word processing and spreadsheet web apps so that productivity buffs can get more work done with less hassle. So far the store comes stocked with about 60 tools, ranging from the seemingly arcane (Supermetrics somehow turns Docs into a web analytics tool) to the incredibly useful (EasyBib takes the sting out of crafting those awful works cited pages). If you're feeling particularly creative, you can start crafting a Google Docs add-on of your own too -- just make sure you've got a nifty use-case in mind or Google will shoot it down. Neat as it is, though, the move is no surprise. Microsoft rejiggered its own web-based Office suite just last month, and courting developers could help the folks in Mountain View keep their edge in a battle that's only going to heat up.