Like with a desktop computer you can't do much with a PDA or smartphone, beyond the basics, without third-party software. As a result, a lucrative market has developed around the application needs of mobile users.

Although there are a number of ways to purchase mobile software, one of the most popular sources is Handango. The handheld software retailar has released the March 2005 edition of the Handango Yardstick, its report on what people are downloading and purchasing for their smartphones, mobile phones, and PDAs.

Ten best-selling applications by operating system:

Palm OS
1. Agendus for Windows Outlook
2. Agendus Professional Edition
3. AOL
4. Treo Voice Dialing
5. PocketMirror Standard
6. Diet & Exercise Assistant
7. Ringo Pro
8. SplashID
9. SplashWallet Suite
10. SplashMoney

Windows Mobile-based Smartphone
1. Papyrus
2. ClearVue Suite
3. SmartphoneNotes
4. Battery Pack Pro
5. CodeWallet Pro
6. Pocket Streets
7. eWallet
8. Fizz Traveller
9. CityTime Alarms
10. WorldMate

Windows Mobile-based Pocket PC
1. Agenda Fusion 7
2. Spb Pocket Plus
3. Pocket-DVD Studio
4. CodeWallet Pro
5. Microsoft Voice Command
6. eWallet
7. CodeWallet Pro Desktop
8. Battery Pack Pro
9. Personal Vehicle Manager
10. Journal Bar

Symbian OS
1. SmartMovie
2. Quickoffice Premier
3. WebViewer
4. Remote
5. WorldMate Professional Edition
6. Handy Day
7. SKY FORCE
8. Handy Safe
9. Handy Tools
10. WorldMate

BlackBerry
1. WebViewer
2. Ring Tone Megaplex
3. Aces Texas Hold'em - No Limit
4. Reqwireless Value Bundle
5. WorldMate
6. PocketMac
7. Sol Mania
8. ScreenEngager Dynamic
9. EmailViewer
10. Card Games: Pack One

The Symbian UIQ-based Sony Ericsson P900/P910 was the number one smartphone adding software by revenue, dethroning the palmOne Treo 600/650, while the Symbian Series 60 Nokia 9500 and Nokia 6600/6620 entered the revenue top five for the first time.

With regards to PDAs, the palmOne Tungsten T Series remained in the top spot for both revenue and software units sold, while the Dell Axim X3 Series and palmOne Tungsten E landed at number two and three, respectively.