Ecco Pro, a much beloved outliner and personal information management application for Windows was discontinued about 15 years ago. But you can still download it and run it on Windows 7 today thanks to the efforts of a handful of volunteers. Even though the software isn't open source a few devotees have continued modding it and keeping it current for modern operating systems. They say that no modern application has yet replicated its functionality.Another piece of software with longevity is Eudora, which as of 2009 was still in use by Steve Wozniak as per an interview with Lifehacker. Wozniak didn't say which version he's using, but since he says it's been discontinued, I assume he's using Eudora 6.2.4 or earlier, not the newer Thunderbird based Open Source Edition. I've heard of people using versions as old as 3. They say they can still do stuff with it they just can't do with anything else.If these were web applications, what are the odds people would still be using them today, more than a decade after they were officially discontinued? And are there any new web applications out today that are so good that 15 years from now users will still be clinging to them? read more..