I don't understand the real difference between Instagram and Twitter. I use Twitter. Twitter can include pictures. That's good enough for me.
Never saw what Instagram offers over it so I never bothered. I guess it has more of a focus on posting images, but sounds too artsy fartsy.
Twitter fits right in my need for "Too important not to say, not important enough to make a blog."
Writing as someone who has three - They're like compact galleries of whatever imagery you want to say. Yes, some people use it for nothing but memes, but it's more effective as a way of conveying a series of images and creating communities based around that format. You might argue that the same could be done with Twitter and to a certain degree that is true, however Twitter:
- is far more text based, and consequentially supports a far more wide-ranging threading system (such as it is)
- allows only 4 pics per post
- does not transition between those 4 pics in any cohesive way (you can't include a 10 pic long panoramic shot from your vacation, for example)
Instagram was always built around being very image and video heavy. Yes, there are still people who use it as a means of social/political commentary, but primarily it's more effective as simply a photo/video journal, a creative portfolio, etc. Captions/hashtags & comments can be hidden away and scrolled past entirely, if that's what you want. I find I'm far less likely to stumble down a rabbit-hole of tangential discussions/arguments on Instagram compared to Twitter.
I have one for SL (which i post to less often, due to the reasons I've stated above), one new one for only for documenting my gardening/interest in bonsai, one main account for my creative output (illustration, 3D modelling, photography).