Some stats:
There are now 750,560 people on Facebook in Ireland
512,820 of them are 25 or older (That’s 68%)
334,040 are 30 or older (44.5%)
When Tweetrush launched, Twitter was pumping out over a million messages a day. Soon after it started hitting 2 millions messages a day.
10 months later and now Twitter is pumping out nearly 9 million messages a day with highs of 350,000 messages some hours.
Very comprehensive social media stats for 2008.