Imagine being friends with someone who worked at Facebook. You'd wear a cool T-shirt and they'd have the same one a few weeks later. You'd invite them into your home and they'd order exact replicas of your sofa and your TV. You'd use a feature on a rival social service and they'd quickly come up with their own version. Yep, Facebook's getting hashtags.

Facebook users already post hashtags, but until now those tags didn't do anything: you couldn't click on a hashtag about, say, Game of Thrones and see 1,000 people going OMG about the current episode. You can on Twitter, of course, and if there's one thing Facebook can't stand it's the thought of people doing something on the internet that doesn't involve Facebook.

Cue hashtag support.

Ads nauseam

Facebook wants to "surface" - a word only used to mean "highlight" or "identify" by utter, utter arses - "some of the interesting discussions people are having about public events, people and topics." By "surface" - *spits* - they mean copy Twitter; trending topics are next on the horizon, followed by Sally Bercow being sued for libel *innocent face*.

It's all about the ads, of course. While hashtags won't contain advertising to begin with, it's too tempting an opportunity for Facebook to pass up - and it's too tempting an opportunity for the spammers to pass up too. If you're sharing your updates publicly, hashtags and trends will be hijacked by spammers and scammers just like they are on Twitter.

Facebook hashtags
Even Bill Murray is wearied by the whole thing

Here's Facebook's pitch to marketers:

"Like other Facebook marketing tools, hashtags allow you to join and drive the conversations happening about your business. We recommend that you search for and view real-time public conversations and test strategies to drive those conversations using hashtags...

"Over time, our goal is to build out additional functionality for marketers, including trending hashtags and new insights, so that you can better understand how hashtags fit into your overall Facebook advertising strategies and drive your business objectives."

We've already got huge in-app ads with video ones on the horizon, news feeds full of people hitting Like to win a year's supply of toilet roll and enormous blocks of sponsored content; now, we're going to get even more exciting ways for marketers to drive their business objectives.

What I've long suspected appears to be true: Facebook isn't a social network but a sociological experiment. The goal? To discover just how annoying a service can become without its users buggering off.