Like any other writing, it's just about knowing your audience.
I mean, are you really going to write "HN (Hacker News)", "YC (Y Combinator)", "HTTP (Hyper-Text Transfer Protocol)", etc. every single time you use those in a comment here?
Is this really the case? I've been using it since it's inception (never used "Indigo" in production). At the time it was a godsend because our company was moving to a SOA (ahh... the dark ages) using Oracle Fusion Middleware, and judging by the job postings over the years I suspect many other non-Java/Oracle houses also adopted WCF.
I did not realize it was considered an obscure technology.
This is the third project I have worked on that uses WCF, and I have been working on the .NET platform since Beta.