Hope you’re doing well!
I just wanted to reach out as I really enjoyed the mentioned blog post! I am a certified Quora ‘answerer’ (for lack of a better word) and Duolingo has become my best friend after moving to Switzerland and trying to learn German!
Are you open for collaboration? I would love a newly updated post like this for 2018. I work for a free software management startup called Smallpdf – where we offer free tools to convert, compress and even sign your PDF files via our spiffy website: smallpdf.com. I think our site would fit nicely within this list! 🙂
Let me know what you think, as well as any other ideas you may have.
PS, please try out our tools for free via smallpdf.com – if you ever need help with your PDF files 🙂