New Delhi, Oct 11 (PTI) There is his cinema of course, his forays into our homes through TV and the occasional interview. But the Amitabh Bachchan connect goes deeper with the indefatigable 80-year-old communicating almost every day on social media platforms as well as a blog, making him India's most interactive celebrity perhaps.       That Bachchan, who celebrates his 80th birthday on Tuesday, handles his own accounts on Facebook, Twitter and Instagram instead of handing it over to an agency or a PR team like many do makes his outreach personal, almost intimate. Shifting gears to remain relevant in ever changing times, Bachchan has a massive social media following -- Facebook (39 million), Instagram (31.4 million) and Twitter (48 million).         Add to this his blog, an expansive, daily musings of sorts, he shares on Tumblr.