There are a lot of people currently expressing new forms of activism, social media is playing a huge part these days.
Most definitely! Social media is one of the biggest ways people get there information right now.
Yes, it's a great way to start what's referred to as 'grassroots' campaigns.
I have heard many references to such, but I am not that familiar with the term. Please tell me more about it. 
Grassroots refers to creating campaigns from the 'bottom-up', rather than from the top-down and are considered as being more natural.
That's very interesting. So the people are supposed to be more involved and there should be less political interference?
Grassroots
A grassroots movement is one which uses the people in a given district, region, or community as the basis for a political or economic movement. Grassroots movements and organizations use collective action from the local level to affect change at the local, regional, national, or international level. Grassroots movements are associated with bottom-up, rather than top-down decision making, and are sometimes considered more natural or spontaneous than more traditional power structures. Grassroots movements, using self-organization, encourage community members to contribute
Media activism
Media activism is a broad category of activism that utilizes media and communication technologies for social and political movements. Methods of media activism include publishing news on websites, creating video and audio investigations, spreading information about protests, and organizing campaigns relating to media and communications policies.
Media activism can be used for many different purposes. It is often employed by grassroots activists and anarchists to spread information not available via mainstream media or to share censored news stories. Certain forms of politically motivated hacking and net-based campaigns