iPhone owners who use the Web-based version of Gmail to read their e-mail have a useful new way to archive messages. Just like what's possible on the iPhone's native e-mail client, mobile Gmail users can now swipe their finger across any message (either from the left or the right) to bring up the option to archive it.
This is honestly no faster than selecting messages using the recently introduced "floaty bar," but it's really neat to see another Web app make use of gestures that users are now comfortable doing on their phones. PopCap, the makers of several popular iPhone games, did something similar prior to the iPhone SDK by letting users swipe their fingers across sets of gem stones in a browser-based version of its game Bejewled--a title that was later released as a native application.
Gmail remains a Web app on the iPhone and iPod Touch, outside of access to it through Apple's native mail client.on the mobile browser version, since the company can maintain compatibility on other platforms like Android. More recent features like the aforementioned floaty bar, have been released to both simultaneously, however the swipe to archive remains an iPhone-only feature for now.