We use them without knowing their meaning Useful information

Useful information – Useful definition, being of use or service; serving some purpose; advantageous, helpful, or of good effect: a useful member of society.  meaning Useful information

1. PAN
   Primary Account Number.
2. PDF
   Portable Document format.
3. SIM
   Subscriber Identity Module.
4. ATM
   Automated Teller Machine.
5. Wi-Fi
   Wireless Fidelity.
6. GOOGLE
   Global Organization Of
   Oriented Group
   Language Of Earth.
7. YAHOO
   Yet Another Hierarchical
   Officious Oracle.
8. WINDOW
   Wide Interactive Network
   Development for
   Office work Solution.
9. COMPUTER
   Common
   Oriented Machine.
   Particularly United
   and used under Technical
   and Educational Research.
10. VIRUS
    Vital Information
    Resources Under Siege.
11. UMTS
    Universal
    Mobile Telecommunicati ons
    System.
12. AMOLED
    Active-Matrix Organic Light-
    Emitting diode.
13. OLED
    Organic
    Light-Emitting diode.
14. IMEI
    International Mobile
    Equipment Identity.
15. ESN
    Electronic
    Serial Number.
16. UPS
    Uninterruptible
    Power Supply.
17. HDMI
    High-Definition
    Multimedia Interface.
18. VPN
    Virtual Private Network.
19. APN
    Access Point Name.
20. LED
    Light Emitting Diode.
21. DLNA
    Digital
    Living Network Alliance.
22. RAM
    Random Access Memory.
23. ROM
    Read only memory.
24. VGA
    Video Graphics Array.
25. QVGA
    Quarter Video
    Graphics Array.
26. WVGA
    Wide video Graphics Array.
27. WXGA
    Widescreen Extended
    Graphics Array.
28. USB
    Universal Serial Bus.
29. WLAN
    Wireless
    Local Area Network.
30. PPI
    Pixels Per Inch.
31. LCD
    Liquid Crystal Display.
32. HSDPA
    High Speed Down link
    Packet Access.
33. HSUPA
    High-Speed Uplink
    Packet Access.
34. HSPA
    High Speed
    Packet Access.
35. GPRS
    General Packet
    Radio Service.
36. EDGE
    Enhanced Data Rates
    for Globa Evolution.
37. NFC
    Near
    Field Communication.
38. OTG
    On-The-Go.
39. S-LCD
    Super Liquid
    Crystal Display.
40. O.S
    Operating System.
41. SNS
    Social Network Service.
42. H.S
    HOTSPOT.
43. P.O.I
    Point Of Interest.
44. GPS
    Global
    Positioning System.
45. DVD
    Digital Video Disk.
46. DTP
    Desk Top Publishing.
47. DNSE
    Digital
    Natural Sound Engine.
48. OVI
    Ohio Video Intranet.
49. CDMA
    Code Division
    Multiple Access.
50. WCDMA
    Wide-band Code
    Division Multiple Access.
51. GSM
    Global System
    for Mobile Communications.
52. DIVX
    Digital Internet
    Video Access.
53. APK
    Authenticated
    Public Key.
54. J2ME
    Java 2
    Micro Edition.
55. SIS
    System Installation Source.
56. DELL
    Digital Electronic
    Link Library.
57. ACER
    Acquisition
    Collaboration
    Experimentation Reflection.
58. RSS
    Really
    Simple Syndication.
59. TFT
    Thin Film Transistor.
60. AMR
    Adaptive
    Multi-Rate.
61. MPEG
    Moving Pictures
    Experts Group.
62. IVRS
    Interactive
    Voice Response System.
63. HP
    Hewlett Packard.

Do we know actual full form
of some words???