As someone who has been hanging around the clan discussion boards for a very long time, I can say that clans have meant a lot to me over the years. I basically spent my time growing up in IRC channels and clan boards. I've made a lot of friends and am still having a lot of fun being in and around clans.
I joined Frost when they asked me to help revive the clan. I had known those guys for a while before they died, so of course I agreed when they asked me to help out.
As a co-leader of Frost I can say, in some sense, that "having" a clan doesn't really mean much to me. Managing a clan, however, does and it's hard sometimes, but interesting, too. It's tough to see people leave, or to find out people you love have become inactive. Recruitment has also been difficult lately. But the responsibility and the ability to moderate a clan, keeping everything neat is what I like about my position within the clan.
I personally wouldn't make a clan just to have a funny/nice/cool tag. The people within are what counts for me.
ps. This thread is pretty interesting, maybe something for off-topic?