The proportion of US citizens who use their smartphones to track political news or campaign coverage has more than doubled (28 percent) in 2014 compared with the most recent mid-term election in 2010 (13 percent). The US votes in mid-term elections on Tuesday.

The number of Americans who follow candidates or other political figures on social media has also risen sharply: 16 percent of registered voters now do this, up from 6 percent just four years ago.

The report based on a national survey conducted Oct 15-20 among 2,003 adults (including 1,494 registered voters) showed that this growth in the use of smartphones and social media platforms is particularly pronounced among middle-aged voters in the age bracket of 30 to 49 years.

Some 40 percent of voters aged 30-49 have used their smartphones to follow this year's election campaign (up from 15 percent in 2010) and 21 percent followed political figures on social media (up from just 6 percent in 2010).

For their part, social media outlets are also rolling out measures to rope in more people in the political process.

On Tuesday, Facebook will place a banner at the top of US users' feeds reminding them that it is Election Day and urging them to share with friends if they have already voted, CNN reported.

Micro-blogging site Twitter is also not lagging behind. It has developed the #Election2014 dashboard, which lets users follow political tweets, connect with candidates and see what others are saying.