An interest group would choose this technique if that was the best fit with its goals and resources.
Grassroots lobbying and mass mobilization is the best fit for a group whose goals are ones that are easily understood and which would interest many people. These goals can easily motivate people to get involved, making mass mobilization possible. An example of such a goal might be changing the laws regarding abortion. This is something that is easily understood and is motivating to many people.
This technique is also good for groups that have relatively little in the way of money. Richer groups might find it more effective to spend money on campaign contributions and advertisements. But groups that have many followers but relatively little money are better off doing mass mobilization because that can be done with less money.
Grassroots lobbying or indirect lobbying involves the mobilization of the general public to communicate their opinions to their representatives or the concerned party.
Interest groups would choose grassroots lobbying/mass mobilization because of a number of reasons which include;
Increased influence- by engaging the masses, it is highly likely that the group will establish contact with influential people who support the cause. These individuals would attract more support for the pending issue.
Increased urgency and importance of the issue- An issue supported by a large section of the public attracts attention to other stakeholders and decision makers. This, in turn, ensures that issues are quickly resolved.
Support assessment- by mobilizing the public, the interest group is able to determine the general support for their agenda among the public. This would help in improving awareness and knowledge around the topic to ensure the success of the campaign.
Established movements for future projects- the interest group grows into a movement that can easily be mobilized for future projects. This alternatively improves the speed and effectiveness of future campaigns.