Well that's the thing, isn't it? Twitter is, just as you described it, a micro-blogging platform ... and FB really isn't a "blogging platform" at all: it's a social networking site with some trivial blogging features tacked on, not quite complementary to LJ (which is a blogging platform, with some social-networking features stirred in that distinguish it from most other real blogging platforms). So FB isn't the new thing that renders LJ obsolete; it's a different type of thing, with complementary strengths. (Like how helicopters did not make fixed-wing aircraft obsolete.)
The thing that updates LJ and replaces it in the same niche, the new to LJ's old is not FB or Tumblr or Twitter; it's Dreamwidth. And DW is (intentionally) very, very LJ-like -- it's not so groundbreakingly different that it makes LJ obsolete; just an alternative with some different features (which I personally consider to all be improvements, but again, not enough so to make LJ obsolete) and a different business model (which is a big deal for some of us).
LJ will become obsolete when (a) it stops keeping up with the most important-to-users aspects of the other platforms in its niche (definitely DW, arguably Wordpress, Blogger, etc.[1]), or (b) when blogging itself becomes a quaint, mostly-ignored backwater (which, despite the attitudes of many FB users, doesn't look like it's going to happen any time soon -- AFAICT, one of the things FB is used for is sharing interesting blog entries you've seen with friends who don't read the same blogs you do, without having your own blog, so FB is (again) complementary to blogs). The equivalent of (b) in my plane/helicopter analogy would be Zeppelins -- blimps are still used, mostly for advertising and special-purpose lifting; there's ongoing research in dirigibles and blimps; but airship passenger lines are a thing of the past. There's still too much active participation in blogging for it to fall into the Zeppelins/buggy-whips/horse-drawn delivery cart category.
So basically, the reason our little 'obsolete' blogging platform still looks so useful, is that the platforms other people think of as replacing it and rendering it obsolete don't even come close to replacing it in the first place. It's only folks' ability to confuse tools in completely different categories (because all "web stuff" is interchangeable, right?) that drags the conversation in that direction in the first place.
[1] I would consider those to be directly comparable to LJ/DW, but a case can be made for LJ's social networking features pushing it into a separate category ... or for WP/Blogger to be obsolete compared to LJ/DW.
Yes, I did notice the scare-quotes
Well that's the thing, isn't it? Twitter is, just as you described it, a micro-blogging platform ... and FB really isn't a "blogging platform" at all: it's a social networking site with some trivial blogging features tacked on, not quite complementary to LJ (which is a blogging platform, with some social-networking features stirred in that distinguish it from most other real blogging platforms). So FB isn't the new thing that renders LJ obsolete; it's a different type of thing, with complementary strengths. (Like how helicopters did not make fixed-wing aircraft obsolete.)
The thing that updates LJ and replaces it in the same niche, the new to LJ's old is not FB or Tumblr or Twitter; it's Dreamwidth. And DW is (intentionally) very, very LJ-like -- it's not so groundbreakingly different that it makes LJ obsolete; just an alternative with some different features (which I personally consider to all be improvements, but again, not enough so to make LJ obsolete) and a different business model (which is a big deal for some of us).
LJ will become obsolete when (a) it stops keeping up with the most important-to-users aspects of the other platforms in its niche (definitely DW, arguably Wordpress, Blogger, etc.[1]), or (b) when blogging itself becomes a quaint, mostly-ignored backwater (which, despite the attitudes of many FB users, doesn't look like it's going to happen any time soon -- AFAICT, one of the things FB is used for is sharing interesting blog entries you've seen with friends who don't read the same blogs you do, without having your own blog, so FB is (again) complementary to blogs). The equivalent of (b) in my plane/helicopter analogy would be Zeppelins -- blimps are still used, mostly for advertising and special-purpose lifting; there's ongoing research in dirigibles and blimps; but airship passenger lines are a thing of the past. There's still too much active participation in blogging for it to fall into the Zeppelins/buggy-whips/horse-drawn delivery cart category.
So basically, the reason our little 'obsolete' blogging platform still looks so useful, is that the platforms other people think of as replacing it and rendering it obsolete don't even come close to replacing it in the first place. It's only folks' ability to confuse tools in completely different categories (because all "web stuff" is interchangeable, right?) that drags the conversation in that direction in the first place.
[1] I would consider those to be directly comparable to LJ/DW, but a case can be made for LJ's social networking features pushing it into a separate category ... or for WP/Blogger to be obsolete compared to LJ/DW.