There are a lot of mail user agents out there.
That list of MUAs is also a tribute to the dedication of the guy who maintains the Display Mail User Agent extension for Thunderbird. His current stats:
Current state of work is:
5936 listed headers, 3818 matched headers (13 FULL, 71 PRE, 3622 A-Z, 112 POST), 3818 headers with icon (64.3% done), 3727 headers with URL (62.8% done)
That is really quite something. The extension is very cool; if a friend or family member emails saying “this thing about my mail doesn’t work”, you don’t have to go grovelling through their headers to see what MUA they are using. Also, if they are using Outlook or Outlook Express, you know they are on Windows, which helps.
(Don’t go and try the addon out straight away if you are using Shredder, though – the reason I was investigating the website was that I was about to report a bug that the header pane disappears entirely on Shredder with the latest version of DispMUA.)
> There are a lot of mail user agents out there.
Yeah. Also, the usage share distribution is broader and less dominated by the big players than for most other kinds of software.
If you look at web browsers, your usage share is more than half IE, more than half of the rest Firefox, and most of the rest is either Opera or Safari. (If you look at rendering engines, it’s even more pronounced, since the next several players after those listed are using the same rendering engines as one of the listed ones.)
Word processing isn’t quite that marked, but it’s still a very strong showing for the big players (MS Word, OOo, MS Works).
Databases are all about the big four (Oracle, Postgres, MySQL, and MS SQL Server, not necessarily in that order).
With mailreaders, though, nobody has anywhere near 50% market share, and if you throw out the four biggest players (Yahoo, Hotmail, Outlook/WindowsMail, and Google, probably in that order), you’ve got over 10% of the market left (maybe 20%), and none of the remaining players has anywhere near 25% of that remaining market share. It’s really a diverse market. Which, IMO, is a good thing.