Which websites / blogs / forums keep you updated on latest trends of digital marketing ?

Considering Digital Marketing , check out Marketingprofs.com

Dear Farhan i suggest this websites for you * http://searchenginewatch.com (For Search Engine News) * http://www.socialmediaexaminer.com (a Good blog for social media...
even though, the topics in social media start becoming boring.
nothing new, but it's worth check it from time to time) * http://www.seomoz.org/blog (SEO Blogm) * http://www.copyblogger.com/blog/ (especially in copywriting) * http://contentverve.com/ (all about content and conversion) * http://www.seerinteractive.com/blog (great SEO and SEM blog) * http://blog.kissmetrics.com/ (Simply, I love it...
awesome marketing blog) * http://www.distilled.net/blog (AWESOME SEO blog...
they are partner with SEOMoz) Hope these list help you

Following Mashable & TechCrunch social media pages are sufficient for following all the news and updates.
However for learning/training..
Google still the best!