The Seven of Cups is Water (connections, relationships, mood) related to the element Air (ideas, knowledge, logic). It may signify teaching, facilitating the sharing of knowledge, or geek/intellectual culture.
The essence of this card is exemplified in busy classrooms, hacker meetups, conferences, and any gathering where people are brought together to share with and instruct one another in any subject.
Additionally, the water nature of this card could point to coming clean about something, and clearing the air as a means to preserving relationships.
The Abstract Seven of Cups is abstract Water (emotions, intuition, love, affinity) related to the element Air (ideas, logic, reason, decision making). It can represent affinity for certain ideas, and emotional connection to certain ideas— ideals in particular. Consider the deep, positive emotions that arise when people devoted to efforts like social justice think about their ideal world; those are wholly reminiscent of the Abstract Seven of Cups. This is a card of idealism.
This card may also reflect a tendency to get lost in fantasy, to engage in a lot of wishful thinking and lose touch with reality.