What does happen to accepted posters if no author attend to present? One of our posters has been accepted with "Strong merit" at ACM DEV 2016. We have finalized the draft and sent the camera ready version to the authority. But this year's venue is Nairobi and a 5 days trip to there will cost about a lot of money. And as a student if I cannot afford to attend the conference, what will they do with my poster? Will they include in their library? If not will it be considered unpublished?

PS: All the co-authors of the paper are undergraduate students and none can afford to attend.
As someone commented, different conferences have different policies. For those I'm accustomed to, conference papers are usually not published in the proceedings if none of the authors show up at the conference.

If I understand correctly your situation, I would proceed as follows:


First, contact the conference secretary and explain your critical situation of undergraduate students with no university funding, asking whether they would be able to provide student support (e.g., fee waiving, cheap lodging in student's dormitory etc.) for one of the authors.
If the previous point is unsuccessful, try at least to find someone from your university who is going to attend and that could bring your poster to the conference, attaching it during the poster session on your behalf. Explain this solution to the organizers and hope for the best.