"And, as for any community, it became an identity marker as it differentiated this site from those who permitted text speak (and and had other shibboleths, such as 'fluffy' language, no swearing, tickers etc)."
I totally agree with this. I also think there was a marked difference in the demographic make-up of the two sites, which has eroded over recent years.
When I first joined MN, I was often astonished by the high level of debate, the clarity of use of language and the general erudition of many posters. I spent several months lurking before I daring to post, and frequently felt intimidated when eventually I did. I remember at the time seeing a breakdown of user demographics which indicated at that most posters where university graduates and a higher than expected proportion had post-graduate qualifications.
As the site has got bigger, not to mention the influx of a different style of user post Penis Beaker, the content - and dare I say it, the level of humour- the site has changed significantly imo. But, I'm pleased to see that text speak is still being resisted.