Downsides:
- It's unprofessional. They are usually teenager level style.
- Most of them are repeated ad nauseam. Reposting an old meme is boooring.
- Trying to fit them in for the sake of having them in is a really pathetic attempt at being hip.
Upsides:
- It can liven up a text.
- It can be really memorable and funny if done right.
- It can really drive a point home.
Do NOT use generic memes for generic purposes. Use of rage faces to express opinions is practically bound to be a failure. Using a meme in role of lorem ipsum (or any other generic sample subjected to given process) is bound to feel pathetic. Using it where a common expression would suffice is awkward.
On the other hand, hand-modifying a meme to make it a perfect fit for a given situation, something that would be hard to put in words to give it enough impact, can really make the impact.
I can imagine you describe a particular compiler directive that really badly breaks the resulting binary directly in opposition to what it should protect against, then you put Scumbag Steve's hat on it. It's hard to describe in words how utterly assinine the compiler behavior becomes, but the picture is worth a 1000 words.
Or there's a case where given system running in a virtual machine runs an emulator under which a virtual machine runs an interpreter that executes a simulation. XZibit made it.
Or there's a simple typo in a script that triggers a small routing bug and brings down an entire data center bringing a whole city offline.
Don't overthink it. Only use simplest variations. Think of the memes as punctuation marks similar to !
or ?
except expressing somewhat more complex emotions, and it can be fine. If you abuse them, though, you lose all benefits. That would be like abusing punctuation, wouldn't it!!!?!!
edit:
oops I didn't notice the example page you linked to. I see you commit a serious crime: using memes without understanding them.
The first meme: "1st world problems". It's used in context of mocking a trivial problem. ALWAYS with sarcasm. In this case it would imply you're supporting long names and mocking ire caused by them. This is not what you claim in your text. You abused a meme badly, used something strictly cynical in a direct, non-cynical way.
Second: Sudden Clarity Clarence. It's to express epiphany, either truly or mockingly. A minor advice does not quite qualify there. It should be either really surprising or really trivial, not something from the spectrum between.
Third: Success kid: It's a marginally known meme about a minor serendipity. Is the achieved improvement of code just effect of blind luck? What do you want to convey through showing the amount of joy it's supposed to cause? The message is unclear, and the fact you used a little known advice animal doesn't help at all.
In essence, know the meaning of the meme before using it, or you risk making an ass of yourself, say, by inserting your own serious opinion into a frame of mockery. Memes are a minefield, and you really need to know what you're doing.
ps.
Concerning number of pictures per blog post, what others address: Use as many as you want, but providing you use them right and make them genuinely funny.
I doubt you'd find enough context in a post of the size you have linked to ever fit three memes in a meaningful and original way. There's maybe enough material for one. If you're a genius, you might squeeze three out of it. Are you?