podosphere

The story

1. Proto-Indo-European*h₁én
2. Proto-Indo-European*h₁n̥tér
3. Proto-Italic*n̥ter
4. Latininter
5. Latininter-
6. Englishinter-
7. Proto-Germanic*natją
8. Proto-West Germanic*nati
9. Old Englishnett
10. Middle Englishnet
11. Englishnet
12. Proto-Indo-European*werǵ-
13. Proto-Indo-European*wérǵom
14. Proto-Germanic*werką
15. Proto-West Germanic*werk
16. Old Englishweorc
17. Middle Englishwerk
18. Englishwork
19. Englishnetwork
20. Englishinternetwork
21. EnglishInternet
22. Englishi-
23. Proto-Germanic*paidō
24. Old Englishpād?
25. Middle English*pod?
26. Englishpod
27. EnglishiPod
28. Proto-Indo-European*bʰer-der.?
29. Proto-Germanic*braidaz
30. Proto-West Germanic*braid
31. Old Englishbrād
32. Middle Englishbrod
33. Englishbroad
34. Proto-Germanic*kas-
35. Proto-Germanic*kastōną
36. Old Norsekasta
37. Middle Englishcasten
38. Englishcast
39. Englishbroadcast
40. Englishpodcast
41. Proto-Indo-European*weyh₁-?
42. Proto-Indo-European*wiHrós
43. Proto-Germanic*weraz
44. Proto-Indo-European*h₂el-
45. Proto-Indo-European*h₂életi
46. Proto-Germanic*alaną
47. Proto-Germanic*aldiz
48. Proto-Germanic*weraldiz
49. Proto-West Germanic*weraldi
50. Old Englishweorold
51. Middle Englishworld
52. Englishworld
53. Proto-Indo-European*dwóh₁
54. Proto-Indo-European*dwi-
55. Proto-Indo-European*dʰeh₁-
56. Proto-Indo-European*h₁weydʰh₁-
57. Proto-Indo-European*h₁weydʰh₁ós
58. Proto-Germanic*wīdaz
59. Old Englishwīd
60. Englishwide
61. Englishworldwide
62. Proto-Indo-European*webʰ-
63. Proto-Germanic*webaną
64. Proto-Germanic*wabją
65. Old Englishwebb
66. Middle Englishweb
67. Englishweb
68. EnglishWorld Wide Webellip.
69. EnglishWeb
70. Proto-Indo-European*legʰ-
71. Proto-Indo-European*légʰyeti
72. Proto-Germanic*ligjaną
73. Old Norseliggjader.?
74. Middle Englishlogge
75. Englishlog
76. Proto-Indo-European*bʰeh₂ǵosder.?
77. Proto-Indo-European*bʰeh₂g-der.?
78. Proto-Germanic*bōks
79. Proto-West Germanic*bōk
80. Old Englishbōc
81. Middle Englishbok
82. Englishbook
83. Englishlogbook
84. Englishlog
85. Englishweblog
86. Englishblog
87. Ancient Greekσφαῖρᾰ (sphaîră)
88. Latinsphaera
89. Late Latinsphēra
90. Old Frenchsphere
91. Middle Englishspere
92. Englishsphere
93. Englishblogosphere
94. English todaypodosphere

Most likely a blend of podcast + blogosphere, it seems to have been first coined by podcaster Steve Gillmore during the opening session on podcasting of the Bloggercon III conference. By surface analysis, pod(cast) + -o- + -sphere.