My bf likes to go on reddit, so throughout the day he'll send me funny pictures (mostly of cats!) and I'll do the same.
My bf does this too! He'll save up the cute pictures he sees throughout the day and then send them all to me when we Skype at night. And he'll save any cute or funny videos he finds so we can watch them together next time we visit.
But, I will add a word of caution for anyone who uses Reddit (or similar sites) or has an SO who does - be aware of how much time you spend there. My bf spends 8-10 hours a day (sometimes more!) on Reddit, and it gets REALLY frustrating for me because no matter how hard I try I feel like I can never contribute anything to our conversations. No matter what I try to share with him - a picture, video, news article, funny story, anything - it always gets dismissed with an "Already saw it" because it made the rounds on Reddit weeks or months ago. Even with current events, I usually can't get him to contribute more than a sentence or two to any given issue because he's already seen it discussed ad nauseum on Reddit. Which sucks for me because sometimes I genuinely want to talk about those things with him. And it sucks to be constantly left feeling like a total dead weight in the conversation because all of your potential topics for discussion have been sapped by some stupid website.
So yeah, just something to consider if you frequent sites like Reddit and your SO is not really into that sort of thing. It does get irritating for the other person after a while.
As for what works for us, my bf and I have only been long distance for a couple months so we're still working that out. We text throughout the day, which actually works pretty well for us. Nothing major, usually just quick texts every few hours or so about what we're doing or how our days are going, though sometimes we will get into a whole conversation. Sometimes texts are the only way we communicate all day, and sometimes we'll Skype at night. Sometimes are Skype conversations are just instant messages and sometimes we'll do the whole video chat thing. Just kind of depends on the day.
We were practically living together for quite some time, so my bf loves my cat almost as much as ( or possibly more than . . .) he loves me, so occasionally I'll send him pictures of what the cat is up to. I also frequently force the cat to join in on our Skype conversations, because we're dorky like that.
It also really helps that we have an activity in common. We both do martial arts - my boyfriend does Kung Fu and I do Krav Maga (and many Krav techniques were taken from Kung Fu) - so it's always interesting to compare notes on what we're learning and how the two styles differ. He's been doing it much longer than I have so he's ranked way higher than me, but I still think it's fun to hear about all the cool stuff he gets to do, and he always seems interested in hearing about what I'm learning too. Plus having something like that in common always gives us a good topic of conversation to fall back on when we feel like we're running out of things to say.
I'm starting to realize that making an ldr work takes a bit of trial and error. What works for one relationship isn't necessarily going to work for yours, and vice versa. You just kind of have to try things and see how they go, and be open with each other about what is and isn't working for you. It's a process for sure.
and also sends me cat pictures 
