The Community Project is likely the least abstract and second most popular of the Immortality Projects. The project encompasses religion, politics, nationalism, sports teams, etc.
These are causes/symbols that are bigger then oneself and that will continue on after one dies. Furthermore these causes are defined by their collective group - in other words they don’t exist without people being a part of them. Therefor, being a member of these groups causes one to feel that they are contributing - that they are part of the necessary collection that defines the group.
Religion
In the case of some religions there is an added immortality benefit of, well, immortality. Many popular religions claim to offer some form of life after death. This component of religion leverages much of the same motivations behind 07 - The Biological Project - that is, the mammalian desire not to die. Furthermore, some religions like Christianity claim suffering in the afterlife for those who are not followers. This attempt to relate familiar physical suffering with a religious decision adds an extra layer of compellingness; as Pascal’s wager showed, you might as well believe.
I believe this two-for-one special of communal immortality (10 - The Community Project) and semi-biological immortality/suffering avoidance (07 - The Biological Project) is what makes religion so compelling. The latter is more self-explanatory: avoidance of biological pain. The former however is much more nuanced and is the component of religion that relates to all the other forms of Community Projects.
Group Immortality
Putting the Biological component aside, the roots of the Community Project comes from a sense of group immortality. These groups/communities are their own life-form that extends beyond the individuals that comprise them. More importantly, these communities do not have a foreseeable expiration date. They are purely conceptual in nature, and because they exist as concepts we can associate with them whatever abstract traits we like.
Sports Teams
Being a fan of a particular sports team is the simplest form of a Community Project as it largely comprises of simple “support”. By support we mean chear when the team is successful (win, score, etc) and maybe wear the teams colors on your clothes. Sure there are levels to fandom, but the bar for entry is pretty low. Go to a foreign city, put on the local teams jersey, and you’re in.
So what compels us to be a fan? As with all Immortality Projects, it’s an extension of the 07 - The Biological Project. The desire to be a part of a group comes from our mammalian roots. We are social creatures by nature; being part of a group is our preferred mode of operating. In the most basic sense, being part of a group offered safety for one’s own life.
You can feel how compelling this association is if you’ve ever been to a sporting event where the vast majority of the crowd is cheering for the same team. When the team is successful, you can easily find yourself celebrating, sometimes through physical connection (high fives), with the strangers that happen to be in your vicinity. Furthermore you can look out onto the crowd and see thousands of people unified in this response. In is here that we experience a brief but powerful moment of immortality, for this unified community does not have the same finite lifespan that we do. It is comprised of young and old, and should the team continue to exist, this community will move through the generations - never dying.
Nationalism
Nationalism is very similar to associations with sports team, but is often more compelling as comes with a more exclusive set of criteria. Firstly there is entry criteria, unlike sports where you can put on a jersey and instantly be a fan, being a member of a nation has some rigid criteria. You either have to be born within its boarders or live there long enough to apply for citizenship.
Secondly, being a member of a nation often comes with an associated set of vague (gradient) values. For example, asking people “what does it mean to be [insert nationality here]?” and you will likely get an array or responses that don’t necessarily align. However the point is not that they are consistent, the point is that people associate with these higher level, often virtuous concepts which also live forever.