And Viber beats WhatsApp into the ground.
I've tried half a dozen SIP products. Many of them look attractive but they all suffer from two major problems;
- No single directory, so it's impossible to know if someone out there has an account
- The audio quality is total crap.
I use VOIP rarely (maybe once every month or so) so it's not a big deal for me. But SIP would be preferable to Skype. It's just not usable.
Wow, Apple should be widely lauded for being able to store each email, including its header, in just one byte!
Even that is awfully wasteful. To store spam wisely you use a counter.
Store spam? I recommend a 1-bit counter set to zero.
I use Emacs for writing; most of it is in XML (usually DocBook, sometimes TEI, occasionally XHTML). I use XSLT to transform it to LaTeX if I want publication-quality PDF, but more often the document is the input to other people's toolchains which want XML first. I occasionally transform to other formats (HTML, Word, or some wiki formats which are largely MarkDown-ish).
I author in XML because most of what I write involves quite detailed and very specific structure, and DocBook and TEI provide appropriate levels of markup for this. I made a conscious decision to go this way a very long time ago, when it was all still SGML, and I have never regretted it.
Most people don't have that level of specificity to adhere to. All the formats you mention have their areas of application, even Word, but there is a growing undercurrent towards using HTML5 as the default format, driven partly by the fact that Ebooks use it. The publishing industry is very interested, as they hate and detest Word, and only use it because its change tracking is useful and it has usable style-editing, which OpenOffice and friends don't have (ie they have no style margin like Word). It was very clear at the XML SummerSchool last month that there is growing support for HTML5 in editing tools, and some new advances in editorial control (eg systems like Xopus, FidusWriter, and Poetica) mean there may even be a way to escape from Word
Disclaimer: editor interfaces are my thesis topic; I have no connection with any of the above except the XML SummerSchool.