From uncles wearing skinny jeans to mothers investing in ra-ra skirts and fathers nodding awkwardly along to the latest grime record, the older generation has long known that the surest way to kill a youth trend is to adopt it as its own. The cyberworld, it seems, is no exception. The proliferation of parents and teachers trawling the pages of Facebook trying to poke old schoolfriends and lovers, and traversing the outer reaches of MySpace is causing an adolescent exodus from the social networking sites, according to research from the media regulator Ofcom. The sites, once the virtual streetcorners, pubs and clubs for millions of 15- to 24-year-olds, have now been over-run by 25- to 34-year-olds whose presence is driving their younger peers away. Although their love of being online shows no sign of abating, the percentage of 15- to 24-year-olds who have a profile on a social networking site has dropped for the first time – from 55% at the start of last year to 50% this year. In contrast, 46% of 25- to 34-year-olds are now regularly checking up on sites such as Facebook compared with 40% last year. Overall, 30% of British adults […]