Remember the Qantas hashtag fail? Of course, you do. The Aussie airline saw the #QantasLuxury Twitter campaign spectacularly backfire late last year.

Now it is the turn of McDonald’s which has also been on the receiving end of a Twitter hashtag fail after it launched promoted tweet campaign that sought to share positive stories about farmers who grow the fast food giant’s food. Sadly for McDonald’s this quickly turned into a major piece of #McFail as it lost control of the hashtag and off it went.

The problems started when McDonald’s switched from its first hash-tag #MeetTheFarmers, for those uplifting farmer stories, to a second one #McDStories, which was quickly high jacked tales of munchies and other less favourable experiences and comments about the burger chain. Here’s the original tweet:

“When u make something w/pride, people can taste it,” – McD potato supplier #McDStories mcd.to/zIlXXu

— McDonald’s (@McDonalds) January 18, 2012

All of this and McDonald’s used the hashtag only twice. One tweeter claimed to have chipped a tooth while another said she had been hospitalised for food poisoning as a result of eating there. Yet another said McDonald’s use pig meat from gestation crates. While @jfsmith23 wrote:

Watching a classmate projectile vomit his food all over the restaurant during a 6th grade trip. #McDStories — j.f. smith (@jfsmith23) January 23, 2012

One of the worst was @MuzzaFuzza who tweeted this, which was then retweeted:

You must have a LOT of diarrhea then. RT @MuzzaFuzza ‎”I haven’t been to McDonalds in years, because I’d rather eat my own diarrhea.”

— Jeremy Peter Green (@JPGClog) January 21, 2012

Social media director Rick Wion told paidcontent.org: “Within an hour, we saw that it wasn’t going as planned. It was negative enough that we set about a change of course.”

However, it was too late for that. It is pretty clear given the Qantas fail that you have to be very careful about the hashtag you employ even more so if you have just had some bad PR (Qantas) or you are a company that strongly divides opinion (McDonald’s).

Hashtags that leave you open or that can be read multiple ways can, as in both cases, spell disaster. What’s interesting is that the original #meetthefarmers hashtag continued to work picking up positive tweets. It had going for it that it was very specific.

It was only when McDonald’s went to a wider audience with #McDStories that it lost control as the wider consumer market tore it to shreds.

One thing is for sure you can not fire fight these things. When a hashtag goes, it is gone.

That was all that it took. The Daily Mail gathered some of the best tweets that rip into McDonalds: