src: url('myfont.woff2') format('woff2'),
@Zelphir tools make it hard to create embeddable fonts with that flag, and your run-off-the-mill designer is programming-illiterate and could only remove the flag if someone designed a Mac app with a shiny "pirate font" button. Moreover, if they are a corporation, you can bring legal charges. If they are some guy with a blog, talk to them, failing that, their host, etc - but keep in mind people who can't buy your font aren't potential costumers anyway, so I'd say free publicity is worth more than the hassle of convincing them to just swap it for the closest thing on dafont.
At the same time, iOS on the iPhone and iPad implemented svg fonts.
From what I see, TTF is lighter than WOFF, so 99% of time there is no reason to use WOFF
If you don't want to support IE 8 and lower, and iOS 4 and lower, and android 4.3 or earlier, then you can just use WOFF (and WOFF2, a more highly compressed WOFF, for the newest browsers that support it.)
In short, font-face is very old, but only recently has been supported by more than IE.
Maybe I'm wrong I'm sure I recall a flag that disabled something like 'desktop mode' to ensure a user couldn't use the font outside of font-face Perhaps that was an earlier spec?
TTF shouldn't be lighter than WOFF. WOFF is a compressed form of TrueType - OpenType font (ttf and otf).
The point of WOFF is not anti-piracy. TypeKit says, "the two main benefits OpenType/CFF fonts have over TrueType fonts are 1) their smaller file size, and that 2) they require far less hinting information in order to render well in environments that allow some form of anti-aliasing."
Then, woff was invented which has a mode that stops people pirating the font. This is the preferred format.
eot is needed for Internet Explorers that are older than IE9 - they invented the spec, but eot is a horrible format that strips out much of the font features.
ttf and otf are normal old fonts, but some people got annoyed that this meant anyone could download and use them.