➽ WebFX Readability Test Tool
I do not yet know how reliable and useful this is, but surely could help to at least experiment with. Based on quick tst on one blog article in German, I guess that Coleman Liau Index may not work in anything else but texts in English. Feedback and opinions are welcome.

➽ iFixit
Wiki-based site that teaches people how to fix almost anything. Or at least it may turn out as a comforting place to find peer support. I have had an annoying zoom button issue on my Panasonic Lumix DMC TZ-60. Every now and then when I use zoom, the video recording goes on. At iFixit I found out that I am not alone, and this is a common problem for DMC series cameras.

➽ LingoJam
Gives all kinds of tools to play with texts.Do notice that you need to test which symbols are in UTF-8, to make them work here at ipernity.

➽ Flip Your Text
The best backwards and upside down text generator that I have found! Only upside down diaresis are not supported. And the best results one gets with capital letters.

➽ Shape Catcher
If you ever need to try find some symbols, then here's a great tool for it. Just draw on the box and search, and you may get surprising results. There are also other tools around to search for symbols, like Mausr and Detexify. Or try symbols.com where you either browse for symbols or ask help from the community.

➽ statcounter
For nerds this gives a lot of useful information on what operating systems, browsers and devices people use. One for example finds out that the majority uses Windows OS (78%), Chrome browser (70%) and have 1366x768 screen resolution (23%) on their desktop/laptop computers. And it is also useful to know that over 50% of users are now having some kind of mobile device.
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Please feel free to suggest more on comments.