These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Face Book
Alt-itis: people often use multiple accounts in social games like Mafia Wars (even though this is against Facebook's policies, as well as those of many other games).
Hashtags. Even when they weren't functioning, some people still posted them on Facebook, while others think they're annoying and only belong on Twitter and Instagram. When Facebook made them actually work, those people were even more incensed.
Even Facebook stickers. For some, it's a harmless little change that can make chats cute (There's even some from Despicable Me). For others, it's a "useless add-on" or "a ripoff of Line Chat".
Not really a meme, but the "Please give me a million likes so that I can get a puppy/a tattoo/a new car/etc" pictures rapidly fell out of favor after they started popping up all over the website for a number of increasingly stupid reasons. Some people have even parodied it, saying "If we get one million likes it won't change a thing because we have to work for what we want".
Similarly, the "X people for [action]" fell out of favor too, which was parodied with groups like "An Arbitrary Number Of People Demanding That Some Action Be Taken".
Recently, it seems to be "Type (Something) that doesn't have a (common vowel/consonant) in its title" to where it's actually parodied.
Double Standard: Facebook's announcement of a new policy has stuck some users as this. The new rules would ban anything that "promotes violence" against women. While this sounds like a good idea many have criticized the rather vague and loose wording as well as the fact that is does not offer the same protections for men. The fact that it bases its judgments and training solely on feminist claims and (misunderstood) beliefs has also drawn some attention.
Good Bad Bugs: If you make a fanpage with the title in Chinese characters, Facebook fails to distinguish whether you're writing said characters as part of Chinese or Japanese and as such the URL will have the characters romanized as if they were part of Chinese regardless of context.
Due to Facebook being Banned in China, Japanese is more likely to be the intended language. It's a bad bad bug in that case.
The "Like" button on many websites, including This Very Wiki, records that you've visited it, even if you're not logged into Facebook. Yes, Facebook knows every site you visit! Yes, all of them.
The aptly named "Stalker Apps." Facebook has always been jokingly accused of being friendly to Stalkers since you can find out every detail you want to know about a person from the comfort of your home, but then facebook started adding mechanics in which you can actually find the exact spot a person is posting from. Now not only do stalkers know everything about you they now know where you are.
The Scrappy: Many Facebook games and apps, especially Farmville.
Scrappy Mechanic: Sometimes it blocks you from sending friend requests and private messaging to people who do not know you for a week for constantly sending friend requests to someone who may not know you. Emphasis on "may".
The "Seen at (Time)" Feature on Facebook Chat. It's a little timestamp on Facebook Chat that lets people know when they've seen messages, but it can also lead to mass paranoia, as one could think that they're ignoring them if they don't reply.
They Changed It, Now It Sucks: Many noticable changes tend to get flak from many users. The more major ones will result in various protest groups with memberships of at least 1 million users.
Vocal Minority: Not everybody feels the need to advertise every single aspect of their lives on the site, but when it's always the same people, to the point where they recurrently litter your wall with their relationship problems, it makes you realise why people tend to look down on Facebook and social-networking in general.
What the Hell, Hero?: The reaction of some when British Police officers arrested a sixteen year old youth after he showed up in order to pick up drugs that they had offered him while posing as a similarly aged girl on Facebook. Various parties have pointed out, what sixteen year old wouldn't agree to doing something this stupid if they thought it had the chance to get them laid? Not to mention that before they entrapped him, he had never done anything illegal.
Not to mention, this raises the question of how certain you are that some of your "friends" aren't really undercover cops trying to bust you? Enjoy the Paranoia Fuel of what might happen if you click that 'Add Friend' button...