When used in any type of text messaging system, HMU is "Hit Me Up." It means that they want you to get back to them - another way of saying "contact me", "text me", "phone me" or otherwise "reach me to follow up on this".
With hundreds of millions of people texting regularly, it's no wonder you've seen a number cryptic looking codes. Acronyms have always been an integral part of computer culture, and they have since spawned a new language on the Internet.
Check out the actual definition of an acronym and text shorthand on NetLingo.com.
Sometimes it feels like parents and téens don't speak the same language. When it comes to texting, chatting and emailing, that's literally true.
Those letters and numbers are an ever-evolving code that kids pick up from their friends. Some acronyms really are harmless, like the now-common 'LOL', but there are plenty that aren't. Check out these essential texting acronyms every parent must know shared by Usatoday.com.