TL;DR: Short for 'too long; didn't read'.
The term 'TL;DR' is used all over the internet as a sort of Millennial executive summary. For long forum posts, people provide a 'TL; DR'--basically, a summary of what the post is about that gives readers a chance to skip the time-consuming act of reading.
Point being: Don't shy away from the Internet's vernacular. You don't need to go whole hog and try to be trendy at every turn, but you shouldn't let proper spelling and grammar stop you from communicating the way that everyone else communicates. TL;DR, lol, nm, imo, btw, gg, rip, b/c, jk, otw, idk, ftw etc. Young people understand this language in the same way that your older clientele understands things like 'whole hog', or 'a bird in the hand'. Acronyms are the new proverbs. And you can use them in your marketing material to connect with over 80 million North American Millennials.