Software development/engineering in general is a field catered to group work. Object oriented paradigms and the internet beg developers to go out there and find other individuals to help them with their work. Source-code control models/programs regulate many common problems and integrated development environments make it easy to edit and test code.
Yet while so many tools are out there, the inane problems with working together will always remain. Lack of motivation, conflicts of interest, other responsibilities, etc all get in the way of the potential that collaboration holds. However, when this potential is realized, we see great things.
Group work is a touchy subject indeed. The fact that individual people can collectively work together on a single task is perhaps one of the greatest strengths we as Homo sapiens posses. And just like how collaboration can be useful in every other aspect of life, so too is it applicable in software development.