All of which can be used to bypass filters and generally cause browser-crashing havoc. For example, this address looks like Google, but it really links to hacker news.
I've never been able to work out if it is an invisible ⨉ character, or a character meant for use when things are invisible. Either way works for Muse I suppose.
It's for mathematics. Some kind of math markup may want to distinguish x times y written xy from a two-letter variable called xy. So the product is x<invisible times>y but is rendered xy.
There's lot of other strange Unicode too. There's things like '' (U2062 INVISIBLE TIMES), ⓞⓓⓓ ©ⓗⓐⓡⓐ©ⓣⓔⓡ ⓢⓔⓣⓢ and sɹǝʇɔɐɹɐɥɔ uʍop ǝpısdn.
All of which can be used to bypass filters and generally cause browser-crashing havoc. For example, this address looks like Google, but it really links to hacker news.
http://news.ycombinator.com/?/moc.elgoog//:ptth