This is a section of the aprs.fi user guide.
Besides transmitting by APRS or AIS, aprs.fi allows you to update your position directly on the web site over the Internet using several different methods: by pointing at your current location on the map (manual position upload), by enabling position updates with a GPS-enabled browser (such as a fancy mobile phone or an iPad) or by using the aprs.fi iPhone/iPad app.
The stations which originate on the Internet (as opposed to APRS or AIS) are called Web stations. They live in a different name space from APRS and AIS stations, and multiple stations can share the same visible name. This avoids the inevitable and usually heated discussion on the ownership of common names. To protect position data transmitted using radio from abusive updates originated from the Internet, a Web station can not update the position of an APRS or an AIS station. Similarly, web stations are not yet transmitted on the APRS-IS - they're only visible on the aprs.fi web site.
As opposed to APRS and AIS stations, the names of web stations support international characters (Unicode/UTF-8). The names are not embedded in links to the stations, and it's also possible to change the name of a station later without creating a new station and deleting the old one.
Web stations do not need to have a valid amateur radio callsign attached to them, although it's a good idea to use one if you happen to have one. Just add a special non-numeric SSID ("N0CALL-W" for example) to make it easier to distinguish from your APRS position.
To change the symbol icon, the web station's name, or the comment text, click on the Favourites (star) tool button in the top right of the screen, and select My stations and bookmarks, and then Settings from the default My web stations item.
This seems to work fine on the iPhone, most new Android phones, and the iPad, and even some laptops with GPS and supported web browsers. Some browsers can figure out their positions even without a GPS, by looking up the previously known locations of cell phone towers or WLAN access points. For this to work, your web browser must support the W3C Geolocation API, and have a working method to acquire your position.
It's also possible to delete the position history of a web station. Click on the Favourites (star) tool button in the top right of the screen, and select My stations and bookmarks, and then Delete from the My web stations station item.
It's not possible to delete the history of an APRS or an AIS station, because the aprs.fi web site has no way of knowing who you (as a web site visitor) are. You might, or might not, be the lawful owner of the APRS callsign. Unauthorized users could well delete other people's historic data, and that could cause some grief. For web stations originated on the aprs.fi web site it's easy to know who created the station, and the user can be allowed to delete it, too.
aprs.fi user guide